We are the second owner of a 2003 Highlander, 2 wheel drive 4 cylinder. The air cond. and heater began to act up. Unpredictable. After some research many owners replied that the wires behind the temp control switch break because the nut that supports the knob and control device comes loose and the wires detach from their soldered point of contact. I have shared my concerns with Toyota and in spite of seeing many many owners with similar complaints, no reply, shame on Toyota. I took my control unit out (very simple) and took the unit that exposed the broken wires to a video repair shop. For 20 bucks the wires were soldered and the problem was solved. No wonder that Toyota is having problems. I hope this can help some others with a similar problem. Martin
I’m the 2nd owner of 2005 Highlander, 4 wheel drive 6 sylinder with the same problem. Although the dealer was prepared to cover 50% of the quoted $900 cost for replacement of the control unit, I was not satisified with their proposal. To me this sounds like a design defect and after further research, I am convinced of this. 1) It is not a part that gets daily wear and tear in my car, which only has 60k miles on it. 2) I was told by the dealer the control system was modified starting with the 2007 models. 3) The dealer’s parts dept. told me they have ordered 4 of these controllers since last October, at $700 each. That seems like a lot to me, living in small town Maine. 4) I got a 2nd opinion from another mechanic who said they see the problem “regularly” and perform the simple soldering fix it requires.
How can we make Toyota step up to the plate and take full responsibility for this problem? Meanwhile, here’s a link to detailed directions, w/photos, to help readers solve this themselves. As Martin points out, it’s easily fixed. Louise
http://www.devalcourt.com/2010/03/fixing-2004-toyota-highlander-ac-and-heat-issue/