I'm actually willing to bet you that the 08 error is your problem. The blend door is how the ACC system changes the temperature that comes out of the vent. If the blend door doesn't rotate all the way into the cold zone, then it will mix the cold air and hot air, giving you what feels like the outside temperature. (The hotter it gets outside, the hotter your heater gets... ) I had this same problem before, only I could not get the system to heat at all. There are instructions all over this site on how to get under your dash and make a quick fix. For me, the gear on the blend door motor had simply slid off the shaft enough to disengage the whole system. The problem with having the dealer do it, is a lot of times they want to remove your entire system under your dash, which is very very expenisve in terms of labor and the unit it's self. Try getting under your dash to see if you can't diagnose it yourself before you spend a fortune. It's going to be a PITA for sure, but it was worth it for me.
Kermit said:Ron, if its working fine then don't worry about it. The door is probably opening 90% so you're not getting any problems, the fault code is occuring because the sensor doesn't register 100% movement.
robw said:Is the stepping motor turning when you adjust the temp? If so, is the gear on the motor engaging the gears in the gearbox? (see the beginning of this thread)