I just bought a 2004 Highlander last Saturday (6/7/08) with 53,512 miles on it. I've been reading here, and elsewhere, all I can find about my HL. Yesterday I checked the heater control and it worked fine. I pulled the knob, and the screw was loose. I tightened it, and after reading some more of this thread today, I'll be putting on some blue Loctite. I've copied the pics from this thread to my computer for future reference. I have a friend who has a HL (not sure what year or model) and I'll be calling him to tell him about this issue. As others have said, this thread is great! I want to add my "THANKS" to wizzer!
Kevin