Defogger Controls Problems of Toyota Highlander

The temperature control on my 2004 Toyota Highlander keeps switching by itself from hot to cold and hot again. I have to actually turn the ac on even when the outside air coming in is moderate because the temperature control will switch by itself to hot and I can't switch it off. This occurs every time I drive and more so when I go over a bump or make a turn. I turn the vent on for outside air, but the temperature control gets locked on to hot and I can't turn it off. I have called the dealer and they have said that it would cost around $1000. 00 to fix it. They want to replace the whole control unit. I have read various forums of numerous owners having this same issue. It seems to be a problem with Toyota not leaving enough slack in a ribbon cable with 3 connections that connect from the circuit board to the control knob. The wires break off from the soldering on the knob. This sounds like a known defect to me that Toyota is aware of, but chooses to ignore. Apparently a cheaper fix is to re-solder the cable, but they refused to do that. I think they should be fixing this for free. This is just another example of Toyota ignoring known issues with their vehicles.

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Heat controller unit stopped working while driving. Windows became frosted while driving because of lost temperature control. Occurred while driving on freeway.

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Temperature knob is loose causing heat to only work intermittently.

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Heater control unit malfunction. Heat to cold switch stops working, dealer states that the whole heater control unit has to be replace. After extensive searching, I have found that the problem is when a nut becomes lose holding the control knob, it shakes and the wires break of make the unit stop working.

The temperature control know in our 2002 Toyota Highlander is not working correctly. The vents blow cold air when the dial is set to the hottest setting. It is very hard to keep the ice from forming on our windows when we don't have hot air blowing. The ice storms in missouri occur fairly frequently and hot air blowing in the defrost position usually keeps the windshield warm enough to keep it clear. However, without the hot air, the windshield ices up immediately and makes driving very dangerous. There are many people having this problem. . Read more...

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The hot/cold knob in my 2002 Toyota Highlander is not working properly. I researched and called Toyota they said there are no recalls on it and they only issue them according to how many parts are sold to repair that vehicle. I looked online and alot of people that own the same year and model of my SUV are complaining about the same issue. Toyota quoted me $805 to repair it when I went in to the service department. He said they have had alot of complaints about the same issue and had already repaired a couple. When I went in to have it looked at I had heat, when I came out I didn't. They told me I had to fix it and there was nothing else I could do. I called the manager of this particular dealership and he told me to bring my car back in and they could set it to heat. Why didn't they return my car in the same order it was in when I brought it to them in the first place.

Ac/heat temperature control switch malfunction. This is a problem that Toyota is aware of and chooses to disregard, since it tends to fail after the warranty on the new part and replacement parts expires before the problem. A small, soldered wire which connects the switch to a circuit board in the dash fails. Should be an easy fix, but Toyota dealers will only replace the entire panel for $800 - 1200. This has happened twice to me on this same vehicle. First time I paid $800, the second time I got a local guy to solder the wire on the old part and replaced myself. Total cost about $10. Shame on Toyota.