And sure enough...
Opened her up tonight and saw the broken wire. I was expecting to see it hanging off but looking at it from a different angle showed it better. It WAS hard to see because it just looked like a section of it was broken out. Anyway, I am another who has performed the repair and voila! Back in business. Of course, it took me about 3 hours - slow, deliberate, careful.
Great thread, great job pointing out a common design flaw.
p.s. I think that one of the three wires is not connected for anyone who gets either full cold or full hot with no switching as that happened to me and replacing the wires was my fix. Not an expert but that is what worked for me.
And sure enough...
Opened her up tonight and saw the broken wire. I was expecting to see it hanging off but looking at it from a different angle showed it better. It WAS hard to see because it just looked like a section of it was broken out. Anyway, I am another who has performed the repair and voila! Back in business. Of course, it took me about 3 hours - slow, deliberate, careful.
Great thread, great job pointing out a common design flaw.
p.s. I think that one of the three wires is not connected for anyone who gets either full cold or full hot with no switching as that happened to me and replacing the wires was my fix. Not an expert but that is what worked for me.
FYI -- The tempy control knob is really a voltage divider circuit. Rotating the knob lowers or raises the voltage (level) going to the control unit. I could see that if one wire or another was broken -- it would either cause the control signal to be seen as hi temp or lo temp setting by the controller.
I just like to add my name on this thread. My 04 Highlander AC/Heat has only hot air. These days in California, with temperature around 100 F, it is very uncomfortable to drive it. I got a solder for .99 at a 99 Cent store, a small wire from Home Depot, and fix the problem. This thread is great, thanks all the people contributed to this thread.
I just fixed mine the other day thanks to this page but I'm afraid I still ahve a problem. Your help will be most appreciated. I soldered in some phone wire (copper). The gauge looked the same. Do I need to use a different kind of wire or did my soldering not hold? The air works fine but the heat will only blow if it feels like it. My original problem was that the air would be on and then intense heat would come out. I would have to throw the temp nob back and forth to get it to stop.
The climate control on my '01 Highlander started having problems a few weeks ago. It would blow extremely hot air randomly when driving with the AC on. I'm guessing the bumps caused intermittent shorts with the loose wires described by everyone.
I brought it to my local mechanic (non-dealer) since I thought it was compressor related. He guessed it was the expansion valve (which I had a hunch it being since my Google search led me to believe it). The work costed me $300 including parts, labor, and new freon.
The problem seemed solved until a week ago when it happened again. Tried to Google the problem another way that wouldn't just point me to the expansion valve. Ended up getting a link to this site which I forgot that I used to subscribe to back when I had other problems with my Highlander.
I just checked and my temperature knob is really wobbly. With the AC on, it stops blowing hot air when I tap the knob gently. Bingo! I already have solder, a solder gun, and 24 gauge wire laying around so it's tomorrow afternoon's project!
My wife's highlander is a 2002 Limited and the A/C started blowing hot air on the driver side while the left side blows cold air. This started happening just after we pick it up from its regular service and the dealership says they did not do anything to cause this. Initially was an intermittend problem but now it just blows hot air like the heat is on on the left side. Our highlander has a different panel with only two knobs and it looks different than the one shown in the photos. Any help is greatly appreciated.
By the way, great forum!
Fixed mine yesterday afternoon. Two of the three wires were broken but allowed intermittent connectivity which explained why the heat kicked in over the AC whenever I hit a bump.
The panel came off easily from the bottom but was much tighter up top. I took a little leap of faith and gave it a good tug and it came off in one piece.
Soldered on three new wires and I was back in business!
Earlier on this thread, someone here asked if it appeared as if the LED's on the panel could be accessed and replaced. There are two LEDs which are user replaceable. It takes a quarter turn on each of the white, round plastic holders to remove them. To replace the bulb with a non-OEM, you would need to solder in a new bulb onto the plastic holder. It could easily be as simple as pulling out the old LED and popping in a new one with the proper lead length but I don't know for sure because I only removed the LED housing to check if it could be changed. I didn't actually tug on the bulb to see if it would just pull out. I think it might. Shouldn't be too hard of a side project.
I want to echo what others have said since Whizzer first posted his fix for the Highlander temperature control unit problem -- a/c operating erratically or not at all (blowing air hot enough to roast a chicken when the a/c unit is "on".) Local Toyota dealer quoted me a repair cost of $1,000 to replace the unit. Two local garages I went to were completely clueless even when I brought Whizzer's photos and detailed explanation of the repair. Obviously they didn't want to touch it.
Fed up with the "professionals," I turned to a neighbor, a retired Ford engineer (who believe me appreciated the irony of my predicament). Short version is that the unit is now working perfectly. Just as Whizzer said, two of the three fine wires behind the temperature control knob had broken when - you guessed it - the nut anchoring the knob loosened over time. My Ford buddy resoldered the wires and had the unit back in my dash in a little over an hour, at a "cost" of several loaves of my home baked VT sourdough bread. Communities like this where experiences get shared, and neighbors like my Ford engineer friend, are fantastic. Thanks, Whizzer.
I have now attached a photo of the panel.
My wife's highlander is a 2002 Limited and the A/C started blowing hot air on the driver side while the left side blows cold air. This started happening just after we pick it up from its regular service and the dealership says they did not do anything to cause this. Initially was an intermittend problem but now it just blows hot air like the heat is on on the left side. Our highlander has a different panel with only two knobs and it looks different than the one shown in the photos. Any help is greatly appreciated.
By the way, great forum!
the two knobs look like their for temperature and blower speed. my gues is YES, the round knob on the left is the problem where the cables are broken and need to be resoldered. also pull the knob straight out and tighten the screw behind it. thats what caused the problem in the first place. as far as electronics that control the flow of the air, i don't think that will be affected once the wires have been resoldered.
my highlander was a v6 2wd with the 3 knobs. my $0.02
Thanks Ptinio for your response. The problem I have is not with the knobs which come out easy but with the panel. The issue is I can't get behind the knobs once I don't know how to remove the panel to access the wiring.......
By the way I read your messages and was able to replace the AC cabin filter which was really dirty. I don't remember having it replace ever by the dealer. I thought it could of been part of the problem but did not help much.
Thanks,
the panel that's faux wood broWN around the stereo/control and vents? thats easy. the way i did it was simply get a spatula or wear gloves and gently push up from the bottom at the two curved butt ends of the panel right by the radio. i'll post some pics tomorrow of my highlander and how I did it. its really easy. i know that when I first did it I was super scared that I might crack the panel. but using a spatula and gloves it came off by just pushing up and pulling out .
it workes and once you get it done, tell your local stealer to !!!!
ok, my issue is finally fixed. it was a switch that is on the high level line that turns the a/c compressor on and the fan on. so, I had two problems, the control switch/panel and the relay switch.. hope this helps anyone that does this fix and still has problems. lates.
@Backdoc7 I am having the same problem you are having on my 2002 v6 Highlander. Where exactly is this relay switch? Help!! Thanks.
Last edited by Thunderbolt69; 05-05-2008 at 06:13 PM.
Re: Heater quit... sort of
Re: Heater quit... sort of
Re: Heater quit... sort of
that I might crack the panel. but using a spatula and gloves it came off by just pushing up and pulling out 
.
!!!!
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