Fixing Toyota Highlander AC/Heat Issue

Fixing Toyota Highlander AC/Heat Issue

My (ex)wife had a 2004 Toyota Highlander that was exhibiting some strange issues with the A/C and heat. In the summer while driving with the A/C on it would randomly just switch to heat and just as randomly switch back later. Sometimes bumps would trigger it or a sharp turn. Same would occur in the winter while using the heat. It would randomly switch to A/C and back.

The problem was pretty annoying but I suspect fearing the possible cost to repair kept her from bringing it in for service.

The issue seemed to get worse over time and with the horrible Louisiana summer heat and humidity quickly approaching she finally brought it in to get inspected and to get a quote.

The shop she brought it to “checked it” and told her it was the “temperature control actuator”. They told her it would cost about $500 to fix.

After getting this information I went to Autozone and O’Reilly’s trying to find this part and what it costs. Neither could find this part. This made me pretty curious and wondered why no one could identify the part. So I went sit in my car and whipped out the iPhone to Google this part and figure out what was going on. I didn’t find any mention of a “temperature control actuator” for a Toyota Highlander but I did find lots of information pointing to what appeared to be the same A/C issue with the Highlander by many people.

I found many complaining that they had to replace the A/C control assembly to fix the problem. The A/C control assembly sells between $700 – $1000, just depends on where you get it. Labor to replace it was between $300-$500. Many reported paying or getting quotes between $1200 – $1500 to replace it.

This was not looking good. I went back inside the store and confirmed the part was $700+ but they didn’t have it. Turns out this was a good thing. It caused me to go back to the car and start searching for that part. This time, I stumbled across someone who was a mechanic who ran across this problem with a client. He mentioned that after he took everything apart thinking he was going to have to replace the A/C control assembly he found the real problem. Apparently the issue is with the temperature control switch (knob) and the three wires connecting it to the control assembly circuit board had broken. This was especially interesting because it really seemed like it made more sense to me. The fact that bumps in the road would cause this to work and not work really made me think this was a short or something along those lines. I didn’t buy the other explanations personally because most of them would have only accounted for it not working entirely and not sporadically.

So…. I decided this broken wire issue had to be the problem and I would at least check this out before spending any money. Figured I didn’t have anything to lose by confirming this.

I went home and went straight at it. Tore the center console apart and got to the control panel. Tore the control panel apart and got to the circuit board (control assembly). Sure enough two of the three wires connecting the temperature control to the circuit board had broken off.

Yay! Got it soldered again and everything reassembled and sure enough, it is working like a champ and cost NOTHING to fix it! Sad that most places wouldn’t attempt to solder it back but rather would just charge people $1500 to replace the whole control assembly.

Anyway… with all that said I thought I would share and detail the process for others in the hopes of saving others a ton of money in the future.

***Couple of New Notes – Please Read***

I highly recommend doing as others have suggested and replacing the ribbon cable you need to solder back together. Part of the problem with the current design seems to be that the ribbon cable is too short. This causes added tension when things are put together and adds to the issue with the wire breaking.

Also, you will or should know how to clean the old solder from the holes on the circuit board in order to correctly solder things back together. Use a desoldering pump to assist with this. If you don’t know how to solder you might be able to find a small local computer repair shop or trade school with people willing to do it for very cheap.

Appreciate all the great feedback this post has been getting, makes you feel good to hear the positive comments.

***End Notes***

5/30/2011 – Just slightly over a year since I put this post up and I think we have easily helped over 100 people either DIY or with slight help (soldering isn’t for everyone, thank God for computer or TV repair shops). At an average of $800 to have someone replace this board or Toyota to fix it well it looks like we have saved about $80,000 total. I know that number is on the short side too. Maybe I should get into the Highlander AC repair business. πŸ™‚

Hope everyone continues to find success with this and please continue to share your success here. It’s a great feeling to get to read all these comments!
***End Update***












Step 1. Remove the knobs. These simply pull right off.



Step 2. Remove the trim panel from the center console. Start at the bottom on one side and then the other. Work your way to the top. This is easily done with no tools and just a little force.







Step 3. There are six 10mm bolts to remove that are holding the center console in place. (Three on each side of console)



Step 4. Remove two screws from both sides of the assembly.



Step 5. Pry the bracket away from the control assembly in order to clear the alignment pins.






Step 6. Unplug the wiring from the control assembly. There are three things to unplug.






Step 7. You should now have the control assembly module completely removed from the console. In order to access the circuit board inside the black plastic housing of the control assembly, you will need to remove the screws holding the rear plastic cover on. Once the screws are removed you can separate the two pieces slowly. You can only separate it slightly as there is a ribbon cable connecting one circuit board to the other.

I pried one side (where the cable was) apart and then used a butter knife to release the connector for the ribbon cable. Once the cable is free you can completely separate the two pieces.





Step 8. Remove the screws and clips holding the circuit board in place.



Step 9. Remove the nuts that hold the switches in place.



Step 10. With the circuit boards and switches removed from the assembly, I could now see the real problem. Two of the three wires that connect the switch to the circuit board were broken. Clean away the old solder and wire pieces. You should have three clean holes on the switch board in which to re-solder the wires to. I’m no expert on soldering but it wasn’t hard at all. If you’re not comfortable soldering something such as this then find someone who is.







Once things are soldered back together you basically need to reverse this entire process to reassemble everything. It really was pretty quick and easy to do and it can likely save you lots of money.

Good luck!

156 thoughts on “Fixing Toyota Highlander AC/Heat Issue

  1. I can’t thank you enough for posting this information. Toyota wanted $700 for a new component and a junkyard wanted $350 for a used one. I just gladly paid my local TV repair shop $25 for 3 new wires and a resoldering job. Got everything back in place and it runs like a top!

    The thing that irritates me is that Toyota knows very well that this is a continuing issue with this panel but does nothing. My 2006 Highlander is the first and probably last Toyota I will own.

  2. Thank you! Thank you! Thank you! I have been dealing with inconsistent heat in my 2004 Toyota highlander for over a year. I was given a quote for $1500 to repair it. I had read your article a year ago when trying to find info about the issue. At the time, I didn’t feel confident that I had the skills to repair it myself. Wow, was I ever wrong!

    Fast forward a year and I was beyond fed up with driving a vehicle without heat in the middle of an Alberta winter. I figured I had nothing to lose and I decided to give it a try! An hour later and a quick trip to a TV repair shop for soldering and it was fixed!! I couldn’t believe that a 32 year old, mother of two with ZERO experience with vehicles (cant even drive a standard, LOL!) was able to fix my own heater while hubby sat on the couch watching a hockey game!

    Thanks for sharing this info and Toyota will definitely be getting an earful from me tomorrow!

    I can’t thank you enough!

  3. Thank you for this post. You saved me a ton of money and time. Took less than an hour to repair (had my own soldering tool.) This is a bad design for Toyota. Thanks again.

    Savannah, Ga.

    1. Thank for the assistance. I was a little worried at Step 7. the plug did not come off the circuit board, instead the ribbon cable came out of the plug. I put it back in and it worked fine. Getting the wires out of the holes was a pain. You need two people to hold everything. Overall it went fine except I dropped a screw putting it back together. Never could find it. Hopefully it is just under the console area and does not get into anywhere important.

  4. Thank you so much for sharing this info – I just used these instructions and fixed my wife’s 2006 highlander! Soldered the wires myself and works like a charm. Local dealer wanted $900 to replace the circuit board.

  5. I am a single mom of 2 children and can not afford to pay for this to be fixed and am going to attempt to do it myself (no experience-just desperate) where do I buy ribbon? Do I need new wires?

  6. Thank you for the great work you did putting this together. I just got a 2005 Highlander and could not get the temp to change (all I could get was heat).
    I went to Google and found your page and after I removed the temp control assembly module I used an ohm meter to check the wires from the back side and sure enough one was broken. I just solder a jumper wire on the back side of the board so I didn't need to remove the board and switch. Long story short, everything works fine now.

  7. I was finally able to fix something without it becoming a nightmare by following your instructions!!!! Everything looked and worked exactly as you said! Awesome post! I can't thank you enough!

  8. Thanks for helping me to avoid the service nightmare! The problem in my Highlander was EXACTLY like the one pictured in this repair procedure. I'm pretty handy and was easily able to do all of the steps myself. But wouldn't have done it without the tutorial.

  9. This was so helpful. Exact same problem with our 2005 model!! Because the ribbon wire was broken so short, I took 3 wires out if a length of telephone wire, and replaced the ribbon on each switch. Works perfect now!!

    Evansville, in

  10. It worked! Saved myself $600.
    When removing the cover (Step 7), instead of reaching in and unplugging the ribbon on the main board, simply pull off the plastic window (it peels right off) and remove the ribbon connector under the window. Much easier and less likelihood of breaking the connector. The adhesive on the window will still allow you to stick the window back on when you are done.

    1. This worked for me, though the Dealer here told me it was probably the ribbon cable and said it was $280 fix, they did not try to push a new board or anything. Then I found this site and followed the instructions and voila, back to normal on my 2004 Highlander. Just in time too, it was stuck on hot and summer is coming.

  11. Thank you for doing all the leg work, I had the same issue for my 2005 highlander and I followed your instructions and now it’s working…Thanks

  12. Thank you for the great tutorial you put together. I am planning to do it by myself, the only question I have, where I can find a new ribbon to replace the old one? Thank you.

  13. Thank you for the great tutorial you put together. I am planning to do it by myself, the only question I have is, where I can find a new ribbon? Thank you

  14. I just bought this car and this went wrong literally on the way home. The people I bought the car from were nice enough to refund me $200. I'm glad I can fix this myself. Thank you so much for posting this and saving me a lot of money.

  15. Thanks a ton! Followed the steps and worked like a charm. Many thanks and kudos to you for publishing this. I owe you a beer if you ever make it out to Seattle!

  16. I just fixed my temp issues using this post as well on my 2004 Toyota Highlander. Thank you so much for taking the time to post this for all of us on the web.

  17. Thank you!!!! 2005 Highlander repaired. just a little help from a friend for solder and I was all set. $0 out of pocket (other than the lunch i'm going to buy for the soldering help :))

  18. Hi – this was the exact issue I was seeing. I asked a shop if they could just check it out quickly after an oil change to see if it was an easy fix. They didn't want to – instead they scheduled a separate appointment devoted to this. Alarm bells went off in my head about how much this would end up costing me – even just to "look". I went searching on this and landed here. Luckily step 1 was all I needed! The nut underneath the knob was really loose – once I tightened that everything has been working perfectly! I'm hoping I caught the issue before the wires broke underneath. Thanks a ton – this was awesome!

  19. Thanks for the help. I worked like a charm.
    Next problem. When you start the car, the Blend Door Actuator buzzes for about 12 secs and then goes off. My local mechanic says that replacing the actuator requires taking apart the whole dashboard, about 8 hours of work. any shortcuts?

  20. Hi Dane:
    Thank you so much for taking the time and the care to post these instructions.
    We had the exact same problem. I took it to my local mechanic with your instructions. He re-soldered the wires and now the AC and the heat work fine. But we are not getting lights on the three temperature knobs at all. Also, the clock lights up during the day but when you turn on the headlights it also goes dark. Any thoughts or suggestions? Would greatly appreciate it. My email is

    1. No worries about the clock going dim when the headlights are on. It's supposed to do that. I had my Highlander for a few years before I noticed and mentioned it to the dealer.

  21. Thank You !! 2006 highlander fixed now thanks to you! In the 2006 highlander the switches are laid out slightly differently and there are more screws but people should still be able to apply what you've shown to that quite easily. Again, Many thanks.

  22. I have a 2005 Highlander. Mine is a little different than your photos in that my temp selector switch feeds a digital temperature display. Over the years, I've been able to tighten the front retaining nut on the shaft to restore function, but just recently, I've tightened and the only way to get function is to put heavy upward pressure on the knob itself while turning. Only with this pressure, can I get function from the knob. Do I have to remove the entire console plate to get at this switch? Looks like there are tabs that press in on the sides. Just wondering if I can take it out of the front.

  23. Wow…….this was exactly my issue as well.

    Note. The dealership told me that the ribbon could not be ordered separately and I needed to order the entire circuit board for $850. I brought the part to a electronic repair shop and they soldered in 3 new wires. Works like a champ

  24. Many thanks. I just followed your instructions exactly and the whole thing took about an hour. My soldering wasn't pretty but it did the trick. I had gotten a quote for about $800 for the part plus about $200 labor. Except for the soldering iron and solder (on sale at Radio Shack for less than $20), I had all the tools already. Its not everyday that you find a 98% discount. My sincerest thanks.

  25. Thank you!!! Just saved me more than $700 (and that price was reasonable). Your description of the problem was exactly the same issue we had with my daughter’s 2004 highlander. Air went out again (and probably for good) last week and was looking at huge repair bill when I found your post. I can’t thank you enough. Just repaired today following your tutorial. Wires had broken off – replaced and re soldered. Worked perfectly!!! Just a note: testing the circuits prior to repair showed they were ok but when you removed the circuit board and turned it over all three connections were severed underneath. My neighbor had the right equipment to test. Not an expert but thought it was strange – just a mom that’s really appreciative for this tutorial and that I was able to do the repair myself.
    Thank you again.

  26. Add another success story to the list! Thanks so much for this. I had tightened up the nut a year or so ago and all was well until the other day when it have up completely. I took it apart and sure enough two broken wires. I took it to a friend who runs an aircraft avionics shop and he replaced the wires. I reinstalled it, but alas I ended up with cold air on the passenger side and warm air on the driver side. I called a place I found online in order to purchase an new heater control unit as I thought that we had damaged it somehow. Anyway the guy on the phone told me that when Toyota's run low on refrigerant that is what they do, so we put in a can of gas and bingo! Air is now 43 degrees coming out the vent.

  27. I am a pretty skeptical person, but I thought I would try this for my mom. Her Highlander had not had heat or air for a few months. Your instructions were great and this post saved her a lot of money. Thank you soooo much!!!!

  28. I have a 2005 Toyoda highlander and the dealership wanted $ 480 to fix the loose connection. I just tightened the nut under the knob and now the air works. It took 2 minutes. Thank you.

  29. Thanks for the instructions! My Toyota dealer knew exactly what the problem was said they had one in the shop with same problem. They said it can be fixed 75% of time for $200 but if they couldn’t fix it the cost would be $800 to replace the whole unit. Shame on Toyota they know they have problem with a simple fix.

  30. did this last night thanks for posting the pics i could not have done this without your help. AC works fine now!

  31. Well Dane, add another $1,000 to money save and not going to the dealership/Toyota! Worked like a charm and it only took my 45 minutes beginning to end, including putting away my tools. πŸ™‚ I'm a proficient solderer so I'm sure that helps.

    When I took mine apart I did not see any broken wires and continuity meter *seems* to indicate all three connected. But, I jumped the 3 wires anyway since I had the thing apart. Bingo! Worked beautifully. BTW, it's my wife's car so I'm on the A-List now! LOL!!!!

    Thank you again and all your effort of writing about it, posting pictures, AND recovering the lost material.


  32. Worked for me also ,I hope TOyota is aware of thisissue,I also had issues with the rear windows falling out of their channel,you can buy an adheisive to make them stay in,the dealer wanted 350$ for each rear window. Great POst

  33. Thank you so much….it is like 110 degree here in DC and no one want to fix this issue. It cost me $15 to buy the soldering tool and I did exactly like your tutorial and it works beautifully. Very nice tutorial…. I really appreciate it.

  34. God bless you! Please don't ever remove this post. I am just so happy that it all works correctly again. I just can't thank you enough.

  35. Awesome! Thank you so much for the great tutorial, Dane. The problem with our 2005 Highlander's temperature regulation was exactly as you cited – wire disconnect from temp control switch to circuit board. Fixed it in snap and saved well over the quoted repair. Quote: $750 plus labor. Actual cost: $0. My hat is off to you, good sir!!

  36. thank you! Everything about your descriptions pictures and notes were perfect! Did this in under a hour works like brand new. Used cat 5 network wire to replace the ribbon.soldering was not such a big deal people should just try it soldering irons and supplies are cheap. just requires steady hands in a little patience.

  37. Thanks!! I have been sitting on your instructions for a while and finally dug in and completed it, pretty simple. On my model I removed the inspection cover to remove the ribbon connection, I didn't know the ribbon was a friction connection and it slips in and out easily. I had friend complete the soldering with new individual wires, no charge, but I will give him some beer.
    You deserve at a least a 6 pack, How do I get you something?

  38. Add me to the list of appreciative people!! Folks like you have saved me hundreds of dollars by avoiding the "STEALerships" at all costs and for that I thank you.

    It wouldn't surprise me if they take the old units, repair them and then sell them to the next customer who brings in their vehicle as a new $700 unit since the repair is so easy.

  39. I have a 2007 Highlander, which my husband just fixed for no cost thanks to you! You are awesome and the pictures were a fantastic help. Thank you!! Thank you!!!

  40. Thank you so much for this post! Both heat and A/C did not work on my 02 Highlander, after some reasearch I found this site, and then after taking apart the control system, sure enough 2 of the 3 wires were broken, resoldered them and now heat and A/C work great.

  41. They say my ’03 Highlander AC doesn’t work because of the switchboard. That it’s broken….is this the same thing???? Thank you.

  42. thanks for this detailed post. My 2006 Hihglander has on dash display and the AC works but not the heater. Any tips on how to debug that?

  43. Had this exact issue and assumed it was related to the knob (well inside) long story short I grabbed soldering supplies for about $15 at Fry’s and now I have a working air conditioner. (My first time soldering too, not pretty but it did the trick)

    Many thanks.

  44. Dane, you are awesome for posting the detailed instructions. I had gone to 3 auto repair places to fix the heating problem and they also said it will cost be at least $1,500.00 to get it fixed because the whole control assembly has to be replaced. One repair shop even specialized in automotive electrical issues. I called 14 different electronic and computer repair places before someone directed me to a small computer replace in Hooksett, NH. Instead of removing or trying to fix the ribbon cable he ran a new wire to the back of the board and soldered it in place. The repair worked like a charm and only cost me $20. Thank You! Thank You! Thank You!

  45. I use this website this morning to fix a 2002 toyota highlander. It worked like a charm. Thanks for the effort helping so many people, you saved me alone over $900…

  46. Worked in that I have heat now. Problem is, now nothing the knob does seems to be able to turn the heat off, and the knob on the right which controls where the air is blown, seems to do nothing. It is stuck at defrost + foot warming.

    Since it is winter, these are things I can live with, but I'll have to tear it all apart again and see if I can spot a short (my soldering skills are not so great), or a problem with the 3rd knob that I may have aggravated by my dissassembly.

  47. THANK YOU!
    It took longer for the car to warm up than it did for me to get through step #1. I simply tightened the nut that is visible in the photo, let the vehicle's engine warm and heat was ready to defrost the windshield. I am prepared to utilize this info again should I need to solder the wires. People helping people a great philosophy to pay it forward. And THANK YOU Again.

  48. What a detailed how-to to fix what seems to be a somewhat common issue with these Highlanders. Thank you!

    I did this repair on a 2003 Highlander and the instructions were right on point. It was mentioned somewhere in this blog earlier, but I also recommend popping off the clear protective window with a butter knife in order to remove the ribbon cable from the main control board. The plastic window was put on with an adhesive and will have enough adhesive that it will stay on when putting back into place on the reassembly portion. The main control board ribbon cable is just a friction cable and just slips in and out of the connector housing versus other ribbon cable types that have a physical connector attached on the end.

    I ended up replacing the broken ribbon cable with 3 individual wires and it works just as well as the super thin wires that broke in the first place. It also seems to be a bit easier to take that route instead of wrestling with the broken ribbon cable. It's probably a good idea to periodically check to make sure that the control itself remains tightened once the repair is complete. It seems to me that the wire probably broke in the first place due to the control being slightly loose creating movement of the ribbon cable wires.

    Thanks again!

  49. Hi

    I just want to thank you.

    Just in case your interested… My wife has a 2005 highlander, which has had a worsening ac issue. We finally brought it to the dealer, who quoted us 1200$ to make the repair. As I was sitting there listening to the service rep, I was googling the year, make, model, and the problem. Your website/blog came up. So while he was yacking away I was reading your step by step Fix. So, I said no thanks, and gave this a rip.

    I had the consule out in literally 15 min, and I swear the torn ribbon cable was almost the exact same image as on your blog. Now the ribbon cable was hanging by a thread so, I opted to just replace the whole cable with three small wires. Cost – free.. Thanks man… My wife is very happy to have the AC back again.


  50. Count up another success! Had the problem with intermittent A/C on our 2005 Highlander (V6 AWD), which cut over to full heat when hitting a bump. Local mechanic here in West Africa wanted to replace the heater core, which didn't seem right. When it became near impossible to keep the A/C on, I decided to get to the bottom of things and found this page. Instead of soldering jumper wires directly to board and switch, I installed 3-pin connectors, and connected them with a servo cable from my RC parts box. Worked like a charm!

  51. Since the thermometer has started reading below zero around the Hudson Valley I decided I better get the heat working on my wife's 2004 Highlander, Your directions and pictures made the job much easier Two wires were broken so I replaced all three.
    Thanks a lot for the help.

  52. Thank you so much for sharing. The instructions with pictures are so clear and extremely helpful. I fixed my Highlander 2002 with exactly the same problem with 2 broken wires.

  53. Dude, you saved me a lot of $. I knew this was an easy fix, and didn't have time to disassemble to discover what you discovered. Thank you, and thank you internet. Sorry service station guys, I know, you need to make a living and you can't do it with cheap repairs.

  54. One thing I would add though, the reason these wires break is that the nut holding the potentiometer gets loose, and every time you adjust he knob, it bends the wire a little, and that action eventually breaks it. I suggest once you re-solder, put a lock washer or some nut glue on that bnut to keep it from getting loose.

  55. Heat went out but Airco OK. I finally fixed it, following your instructions.
    It was the Wire. Now both Heat and Airco work again. Thank you for your
    documenting this procedure. You saved us a bundle!

  56. Wow!!! I have stressed about trying to figure out how to fix. Followed the instructions, disassembled, and found both temperature and fan knobs both detached. Bought a very small soder (small pen point) for $25 at Lowes. Sodered all points and it solved the problem. THANK YOU FOR THE ADVICE.

  57. Piece of cake! I cleaned the circuit boards and the controls before I put the assembly back together. I have a printed circuit board shop, so I took advantage of it.

    Excellent detective work that saved me almost $1000!

  58. Does this same problem occur on the systems which sets the desired temperature on a digital display? My 2001 Highlander temperature control quit responding to the changes from the knob. (the nut was loose but just tightening it did not fix the problem). I have pulled off the trim piece (step 1) and everything looks exactly the same as the pictures but didn't really want to proceed unless I had a little more confidence that the broken wire problem is also the probable cause on this type of unit.

  59. Add another $900 to the tally of $ saved! It took two tried to get it done but my daughter now has heat in her 2003 Highlander. I highly recommend that you clean out all of the old solder and run new wires. It also helped to tin the wires befor soldering them in. I used 22 gauge bell wire and it did the job. Thanks again for the awesome tutorial and when in Wisconsin I owe you a brat and a beer!

  60. Great info! I used your narrative and pictures along with U-tube videos. Soldering was a little tedious – all the connections are within about a half inch total so it took a little trial and error to get wires configured. Took about 2 hours but could do another one in half that time. Was a little hesitant on removing trim but it comes off just as advertised starting with an old credit card. Thanks for the help!

  61. My 2006 Highlander has the same intermittent problem. After pulling the knob, I don't see the ribbon cable or solder connections. Instead, there are three pressure connections. So if the nut on the pot becomes slightly loose, the connections are broken. First I tried simply tightening the nut. But the alignment was off and I only got lukewarm air in all positions of the control. So I loosened the nut and applied a little counter clockwise force on the pot while I tightened the nut. That helped but I only got hot air in all positions. A little more fiddling around and things are working again. Time will tell if this lasts. I suspect it is temporary. I may have to rip the dash apart as per your instructions and change those pressure connections into wired connections.

    1. Your problem sounds exactly like mine. I have the digital screen on the 2006 , with only 2 knobs, not 3 like in all of the pictures I keep seeing. When I tried tightening the nut, it seems like it's stripped. Is that what yours did? I didn't know if I could take the nut off or what next?

  62. I read your directions and viewed the pictures, showed my husband and thought he would do it himself but he let a mechanic he knows do the work and was charged $250 for that job plus r/r spark plugs for my 2005 Toyota Highlander. Thank you so much for the info which the mechanic did not know could be done instead of buying a new circuit board. So we all learned. Thanks again for sharing your knowledge.

  63. Thank you so much. Problem on my 2003 Highlander was just as you said. Broken wires to the middle knob. Toyota Shop said $1000 to fix. They said they'd have to replace the circuit board. I took the board to a TV repairman and he soldered my problem and charged me $25.

    You are the man! It's great to have heat again. THANK YOU many times over.

  64. Tried this and appeared to work (with 3 jumpers in place ) for about 3 weeks. Still works when driving but started dropping heat when you are stopped and the engine shuts off. Tried to resolver but made no effect. Is it possible that I burned up the board or should I go in and completely clean out the holes in the board and use new cable?i thought I was careful to not over heat and used a digital soldering station bower end from a EE coworker. is there something else that shuts off the engine while stopped as it seems (when it's working ) to cycle engine on and off based on temp setting and or fan being on/ off. Thanks for your help

  65. Another Happy Camper here. After 6 years of messing with the knob, she's working correctly again. My soldering talents aren't what they used to be, so the old adage 'always time to do it over' applied! Also found its not necessary to remove the 6 bolts that hold the mounting bracket in. Hardest part was getting the 3 plugs to release. Thank You!

  66. You have another thankful fan of your blog. I have a 2004 Highlander and your directions were very clear and helpful. You did a great job investigating this problem and documenting how to fix it. Having heat and defrosters are must haves in MN. Thanks for your efforts.

  67. I completed the repair and the temperature gauge now works perfectly. However, the clock and thermostat display don't illuminate when you turn on the lights like they should, and they are on when the head lights are off. Somehow I reversed the display illumination. Any thoughts on what I should try to fix this?

    1. I have the same problem with my 2004 highlander since fixing A/C. Did you ever get that fixed? If so, what was it?

  68. Omg man you are a freaking life saver!! Worked and it was so easy. Thanks man!! I’m actually between jobs right now which is why I’m having the time to do this, but if I was able I would totally have donated to your cause I wish you the best of luck

  69. A huge thank you for saving me too much money. I did have to spend $30 on a soldering iron and solder. πŸ™‚ I'm not a computer guy so it could be me, but I couldn't figure out how to donate to your iron man fund. It said that the campaign URL could not be found. Anyway, again, a huge thanks.

  70. Thanks a lot to post this issue. I followed your instructions and the job is done. Thanks again to fixed hot and cold air blowing issue on my 2003 Toyota Highlander and also save lot of money. Wishing you.

    1. I followed this procedure and it fixed the problem on my 2003 Highlander after a quote from Hendrick Toyota of Apex, NC for $987.00 to replace a "FRIED" control board. My cost was $21.65 for a pencil soldering iron. Thanks for all of your time and consideration on creating this TIP>

    2. Notes on 2003 Highlander air/heat switch problem and this is all my humble opinion.
      1.This is a basic design problem in that the control board is connected to the switch with 3 wires that are contained in a ribbon cable. By using a ribbon cable, that allows for zero lateral movement between the board & switch, the two parts must be held firmly with absolutely no movement allowed between them.
      2.Movement of the switch when selecting the switch options causes slight movement of the ribbon cable. This movement causes stress on the wires at the board connection which causes the wires to break after many movements of the switch.
      3.A ribbon cable should have NEVER been used for this application because of the possibility of movement between the parts. Three separate wires should have been used which would have allowed slight movements between the parts without the wires breaking because of stress on the connections. I believe that Toyota should be responsible for the cost of this repair because of the design problem.
      4.Several hundreds of people have had this problem on Toyota Highlanders where the wires between the switch and the control board break. If ALL of these people paid the Toyota price of $987 to fix this problem then this would be well over $100,000. The fact that Toyota offered me 2 prices for a fix leads me to believe that Toyota has full knowledge of the magnitude of the Highlander switch problem.
      5.The Highlander owners, that fixed this problem, did not require any special training and most if not all of them are not electronic technicians. I am 76 with some knowledge of computers and replacing a broken wire is not that difficult. If I had to do this repair again I believe that I could do it in less than an hour. I would be happy to demonstrate to the Toyota technicians this switch repair procedure.

  71. I have a different issue. I need to replace the blend door actuator for my Highlander 2005 base model. When I turn the AC on, passenger's side works, but driver's side does not. I just can't find anywhere that says where it's located and how to replace it. Please let me hear from you if you know how to handle this. Thanks!

  72. Nice Job – I actually ended up completely replacing the ribbon cable with 3 individual copper wires. I made them nice and long so that the "stretch" issue wasn't an issue any more.
    Thanks a million (well, (about $1,500 anyway!)

  73. Same problem…2015. I had this issue back in 2011 with my 2005 Highlander (I still have). I took it to the dealer, they tightened the bolt, sent me on my way, and it worked for three years. It's now been happening again and I am trying to get Toyota to fix it because now it's not the bolt, it's the whole unit and $1000 to fix. First, I asked why the issue back in 2011 wasn't tested more thoroughly and was told that obviously they fixed it because it worked after that. Fine, but now it's the SAME ISSUE. I am contrary by nature and refuse to believe that this is a "wear and tear" issue for an "old car". I live in southern California…I use the air conditioner/heat for less that four months a year. Toyota dealer rep told me that non-use may be the problem, or possibly vibration. Also she asked me "have you just considered trading in the car?". HUH? It has 78,000 miles on it and I've only put on 50,000 of those miles! Doesn't this fly in the face of how long these cars are purportedly supposed to last?
    I will show your fix to my mechanic and see what he says…maybe he can do it. But…since there are about 20 or so google pages devoted to this problem, why isn't a recall issued? How can we do that???? Thank you for the info and I hope you have an idea.

  74. I was able to fix my wife Toyota highlander 2004 using your tips. Dis-assembly was not difficult, but soldering was tough for me. I used the same wire and it was very tough soldering. I took it out to a tech to solder the wires for me at no charge and he was able to do it. Everything started working fine now. Kudos to you.

  75. thanks a million for your post in which we are having the same problem with our highlander. People like you should be rewarded. I will tackle this circuit as soon as possible.

  76. My 2005 Highlander was set on air conditioning and would seemingly randomly start shooting heat out full blast. After reading this site, I talked to my mechanic who recommended an electrical guy. He fixed it for $100 + tax, saying the wires were loose going to the circuit board. He also tightened up the knob that was loose as well. We got it fixed yesterday and haven't needed the air yet so I guess time will tell.

  77. We just started having this problem with our 2004 Highlander last week. I'm glad I found your post. It saved me a lot of time, because I'm sure I would have opened it up and spent a few hours looking for the problem, and may have spent money needlessly. I suspected something like this, and now I know just where to look. I'll probably open it up tomorrow afternoon. Thanks!

  78. Worked for my 2004 highlander as well after taking the original poster's article to a mechanic in Oct 2013. ( Prior mechanic said entire AC panel had to be replaced for $800.)Fast forward 19 months and I started having same issue so taking it in again tomorrow. Hoping it can just be fixed again. Anyhow – Thanks for posting this valuable information!

    1. As always, think about DIY repairs, be patient, follow all the guidelines, be persistent, and take time to do it right……Don't be intimidated by the job you have at hand……..Disassemble the dash/radio control pod, and add extra solder to the broken ends………DO NOT WORRY about all the other plugs, UNLESS you see a broken connection……Solder the connections to reinforce, and resolder the broken ends of the temp control………Take your time, and reassemble everything in reverse that you took the control pod apart….

  79. I took my 2005 Highlander to the Dealer O'Brien's in Urbana, Illinois to fix the heater/AC controls and they basically told me….SCREW YOU!!! Another mechanic got scared and put it back together, found a place in Iowa and they tried but, it was too far gone. Can't find one in the recycling plant so, I guess I will irritate the Wife and go buy a used Chevy…..then, maybe set that stupid Highlander on fire. I HATE TOYOTAS!!!!!

  80. Where did you buy the new ribbon cable? The local car place in my area did not have one. Your thoughts and help are appreciated. Thanks.

  81. awesome you would think this would be a recall toyoya got some of us but not all of us your the best thanks now I can get rid of this damn blanket for the winter you put a smile on my face thanks master technician,,,,,,,,,,,,,,,,,,,,

  82. My 2006 Toyota Highlander temp control is for the digital display of the temp and it only has a know that changes the actual numeric temperature that shows on the screen. Mine seems to be doing similar . We can tighten the nut a little but it seems to just spin around like it's stripped. The fix works for about a day, but then stops working. Does anyone know if the setup is the same on these digital units with the 3 wires that get disconnected as it looks different than the pictures and once you pull the knob off you see something different. Any ideas how to tighten the nut without it spinning ?

  83. I have a 2007 highlander – bought used- I think it may have the same problem ! Intermittent heat ! I mentioned it at a dealer while there for brakes ,oil – they said "seems to work fine now" . I'm going to try your prescribed technique ! Jb

  84. Thank you for the well-documented and illustrated explanation of the fix to this problem. The A/C and heater in my 2003 Highlander is working great again!

  85. I've been dealing with this issue with my 2002 Highlander forever. The dealer fixed it once and i'm sure that he just resoldered the wires or tightened the nut. The worked for four years and i couldn't get any of the local idiot repair shops to "look at the electronics behind the knob". Today i ripped open the system determine to fix it myself. What did i find? One broken wire and one just hanging on. I"m struggling with the soldering but i'll get it.

  86. Anybody have any other ideas? I followed the steps which were awesome but didn’t see any wires disconnected. I just ed tightened the bolt on the ac knob which was finger loose.

  87. I have a 2002 Highlander. I see these pictures are for the non-auto climate control, three knobs. I have the AUTO climate control version meaning there are only two knobs and button that says 'Auto'. My left hand sided knob is the temperature control. I am experiencing less control meaning that when I adjust the actual temperature, it doesn't always respond but sometimes does: a short. After reading this, would you think that I am having the same issues that everyone is having even with my Highlander being the Auto version? Thank you so so much!

  88. That worked perfect. Great piece of work posting this fix. Toyota was going to charge $1,500 to replace the heater a/c unit. The labor was $300 for removing and reassembly. It took me less than 10 minutes to remove the unit, 15 minutes to solder new wires and another 10 minutes to reinstalled it back in my Highlander. I saved $1,500!


  89. Great description – I went through it just as described, and now it works beautifully. We actually took it to a mechanic, who misdiagnosed it – should have tried your solution first. Thanks for putting all this together!

  90. I had the same issue with my 2003 Toyota Highlander. My "mechanic boyfriend" tried to fix the A/C Heater control panel with no luck. So we wind up buying a refurbished one off of The guy who does these part was really helpful, you pay and upfront core deposit and then they mail you the refurbished one and then you mail your broken one back to them. It winded up costing me around $200 and then to find out that wasn't the only issue. Now my Servo Airmix door stopped working and I now am faced with having to replace that. I went by the shop down the street to get it fixed last summer and they told me it was gonna cost me $750 included the part which they guy said cost him $175. I passed once they opened the door the heat worked again spent $50 to have them leave it open, now I am over it, right now I only have heat until I close the door then the AC come back on. So my question is does anyone know if they had this same issue and where to find said part? It is the blender door behind the glove box but there is so many different prices and options IDK what is what. Help lol?

  91. It worked here too (2004 Highlander).
    Almost seems like the loose nut on the temp knob may have caused the wiggle which caused the wires break at the solder joints.
    Something to consider for maintenance work… ie keep the knob bolt nuts tight ?
    Thanks much for the guidance.

  92. You're still helping people out after so many years! I was going crazy with the on-again off-again nature of this problem. Finally got hubby off his rear and he was able to fix it in about half an hour. Thanks double-bunches! I just wish the darn known brake actuator problem was as easy to fix. πŸ˜›

  93. i would like to thank you for your post!
    We took our 2005 highlander into our local toyota dealer here in northern ontario and were told that the only fix was to buy the new module at a cost of $1745.00 canadian plus labour! after a $120.00 diagnosis charge!
    I called my wife and she found your post so seeing as i had nothing to loose i disassembled the module.
    It was a bit tricky to get the wires all lined up and it is not a pretty fix but in less then an hour i got it reassembled.
    Plugged it back into the truck and good as new!
    ThankYou so much!

  94. Nailed it!!!! This was exactly my problem, all three wires had broke off. I soldered new wires on as prescribed and bingo instant cold air which is a great thing to have in Alabama summers!!!! Thanks so much for your solution guide, you saved me a ton of money!

  95. You're my new favorite guy! A couple of hours later, and the breath-of-Satan that had been emanating from my vents is replaced with the icy-cool caresses of the whispered sweet-nothings of a hundred Viking princesses. Thank you!

  96. Came across this info over a year ago, and with the warm weather here, I finally took the time to do this today. Really great info. As soon as I came across this post, I knew it was the issue I had with my 2004 Highlander. Took a bit of time, especially the soldering work. Hard part was prepping the area to reattach and resolder the wires in place. Tested everything for a few minutes when done and it seems like it’s working great. Looking forward to not sweating like crazy on hot days and not freezing when it’s cold out! Thanks so much for the info!

  97. Let me add one more – thanks so much for this, I just bought a 2004 Highlander and it had this exact problem, right down to the loose nut holding the dial in place and two broken connections. I was very happy to be able to fix it myself!

  98. Wow! Looks like my problem will be solved soon. My 2005 is stuck on full heat this morning. Halfway to work it started to work again, probably went over a bump , I'm going to go through your DYI here and see if they soldering points is loose. Thank you so much for taking the time to write up this tutorial. I'll update this forum when I'm done. Thanks!

  99. That was it!!! The nut was loose causing strain on the wires. The two on each end were broken. Thank you for posting this!!

  100. I had the same problem with my Grandmothers car. I did the whole process, had the pieces soldered at a mechanics and put it all back. It is still blowing hot hot hot air. I checked and filled the freon, still hot… Does anyone know if I missed something or what else it could be?


  101. I'm a retired woman seeking advise.
    I also have an ongoing issue with the air switching from cold to hot. After various expensive quotes from Toyota and other garages, a friend popped the console button covers for fan and temp off and tightened the screws behind it and found that to be a quick fix. It worked until recently so I need to get them retighten again I guess since breaking down a console and soldering is not an option I can do myself.

    Bigger problem is my a/c not cooling. Ended up spending $1200 for new compressor in 2014. In summer of 2015 right back where I started from. With compressor under warranty, I took back to same garage and was told now the condensing unit needs to be replaced at $400. Discouraged from spending so much money and only getting a temporary fix, I opted to recharge with coolant and considered selling my 2001 highlander. Decided not to sell as it is a very smooth, nice running suv except for the a/c, so I've held onto it. This summer, 2016,same problem. Bought refrigerant myself and watched utube videos to learn "how to" and saw that the L cap had to be removed so I popped the hood and discovered there are no caps on what I think are the H and L valves on the a/c line. Can not having caps cause the refrigerant to leak out?

    Need to find someone who will recharge it for me with the refrigerant that I purchased and buy replacement caps? Any suggestions or recommendations for Summerville, SC?

    1. Hi Yes not having caps will let a very small amount to leak out,which will over time cause it to be low on refrigerant .you could try recharging it on low side your self with A AC pro set up kit but if gauge swings around unsteady or yours have sight glass doesn't show steady stream of refrigerant then system needs vacuum out to remove air and moisture..Maby garage was trying to save you money but if you replace a compressor standard practice is to replace condenser coil and expansion divice in system for warranty to be honored on a new compressor because debri from old compressor is in system .

  102. You are a saving grace…if you are ever in Rosarito, BC….look me up so I can take you and the Missus out for lunch – Fish Tacos and coronas!

  103. Perfect instructions, and the repair went great. From the Toyota handbook I was told to disconnect the battery so there would be no chance to set off the air bags, but since you didn't mention it, I didn't, and it worked out OK. I went to Auto Zone to get a trim stick to remove the dash panels, but all they had was a kit for 30 bucks, so I got two $1 plastic putty knives at Home Depot, sharpening one to a near point and leaving the other one whole, and they popped the dash trim right off. That other comment was right, the cause of the break is the loosening of the nut on the temp knob. Who would ever think of inspecting that? Finally, you don't need a new ribbon cable, just resolder three new separate wires.

  104. Having this problem here in Louisiana–and at the WORST time of year. This girl is going to do her best to do as you have instructed, as soon as I find a soldering kit lol. Thanks to you!! Lysa

  105. For those wondering where to buy replacement cable, just use the Ethernet or cat5/6 cable. Go to any stores and buy an Ethernet or computer cable (short 1,2,3 feet is fine) you might already have one from your used Comcast or ATT modem/router.

  106. Thanks for the help it worked.I replaced the wires with a ribbon wire from radio shack and made it longer.Saved on my diagnostic time.on this hot humid month.

  107. Hi! The first time this happened… A couple of years ago, it fixed the problem. Re soldered the wires. Now it is happening again…took it apart. Solders look fine. Now what?? It's summer in FL! Melting in the school pick up line! Help, please!

  108. We are currently going through this problem with our 2004 Highlander we purchased used in 2012. Very well maintained vehicle from previous female owner but the a/c after we had it charged blows cold and when we hit a bump blows hot air. In the winter the opposite it blows cold air x 1 yr and a half. Yesterday I happen to gently pull the a/c knob and it came right off and this is when I mentioned to my husband I believe the problem stems somewhere in this knob and behind this panel. We were getting so frustrated 😭😒 because we take care of our vehicle. I wonder if this is an item that is recalled by Toyota. If not it should be!!! Thanks a millionπŸ’°πŸ’° for posting!! You just don’t know how much of a help this article πŸ“„πŸ“‘brings!!! I’ve searched high and low for help πŸ˜πŸ˜ƒ

  109. We are currently going through this problem with our 2004 Highlander we purchased used in 2012. Very well maintained vehicle from previous female owner but the a/c after we had it charged blows cold and when we hit a bump blows hot air. In the winter the opposite it blows cold air x 1 yr and a half. Yesterday I happen to gently pull the a/c knob and it came right off and this is when I mentioned to my husband I believe the problem stems somewhere in this knob and behind this panel. We were getting so frustrated 😭😒 because we take care of our vehicle. I wonder if this is an item that is recalled by Toyota. If not it should be!!! Thanks a millionπŸ’°πŸ’° for posting!! You just don’t know how much of a help this article πŸ“„πŸ“‘brings!!! I’ve searched high and low for help πŸ˜πŸ˜ƒ All the way from Pennsylvania

  110. Thanks for sharing solution for ac/heat issue. It turned out to be exactly as you described and was very simple to repair. Thanks!

  111. I have a 2010 Highlander – same issue with the heat/defroster/AC control. The directions are all good and I am anxious to try the soldering fix. However, the console on my 2010 is different from the older model Highlanders. The console centerpiece is not a one piece plate that I can pop out. Anyone have any experience pulling the center radio/control cover out of a 2010 Highlander?


  112. Thank you sir!.I really want to let you know how much I appreciate what you put out here to the public.You helped me and my wife a lot!

  113. THANK YOU!!! It worked!!! I ended up replacing the small 3-wire band with 3 new separate wires. My wife is a happy woman now.

  114. Thanks! Followed the instructions for my 2006 Highlander Hybrid. Found the disconnected wires once I got everything opened just as you indicated. Only issue is that one of the posts on the plastic box was broken. Had to used needle nose pliers to hold the plastic post to remove the screw (attached to circuit board). Otherwise, very straightforward. Working perfectly now at a cost of $0!!

  115. Thank you for sharing this!!! I’m having the same issue! I changes the theromostat & its still happening! Will show this to my mechanic! Thank you again!!!

  116. Thank you for this!!! After getting a $1500 quote from the Toyota dealership, I googled to know what I was getting into. I’m sure the connections are going bad, but all I had to do at the moment is tighten the nut for the temperature knob. It had a little wiggle which caused the system to switch back and forth between hot and cold.

  117. Thank you for this posting. This was the exact issue and solution for the temperature control circuitry on my '04 Toyota Highlander. I found someone to help with the soldering, and the problem is solved!

  118. I’m so glad you took the time to post this, thanks! Another Toyota fixed! To think this is still helping people 6 or 7 years after posting it, is a testament to the freedoms we enjoy in this country and the generosity of people to share their problems and solutions. Feeling grateful.

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