Heat/AC

#1

I have a 2002 Ford Explorer (V6) and the temperature control for the heat/AC is malfunctioning. When you try to change temperature or vent settings (not fan speed) you hear a thunking sound coming from behind the dash, and you either get very hot or not at all hot temperatures. I think the culprit might be a vacuum hose, but I’m not sure. Any help narrowing down at what and where to look would be appreciated.

#2

Does this have electronic controls (thermostat) or manual (knobs)? The blend door is probably electrically-controlled. It sounds like the door is getting jammed and then freeing itself. If probably will get stuck soon. They can be hard to get to (pull the dash back), but I don’t know for the Exploder.

#3

I have manual knobs. Also, the thunking sound is repetitive until you run the fan at full blast.

#4

A common problem for those is for the plastic blend air-door to break where it connects to the motor. This sounds like your problem. The blend air door is electric, even with the manual climate control. It’s a cheap part, but a lot of labor is involved in changing it out. There are some work-arounds that might work. Search the web for them.