My 1990 legacy wagon has issues with the heater controls, there is a constant squeak squeak squeak from under the dash, sometimes goes away when you shut the ventilation system off. Also, the heater/AC controls dont' always work, the air doesn't like to come out of where you have it set (when I first got it, air blew out the defroster vents regardless of where you had the controls set, then after a while it would switch) and the blower fan works when it wants to. For example, tonight I was trying to charge the AC and I'd hit the "A/C" button and the light would come on, but the compressor wouldn't engage, and if I started pushing buttons I got the AC to kick on and the fan to come on, but it's really annoying like in the morning when I'm driving to work and freezing my arse off because the only air flow I'm getting is the natural flow through the car, same deal on the way home when its 90+ out and I've got the windows down and the sunroof open because the fan won't work... but it's intermittent so I'm not too sure where to start, I suspect that the control unit is bad but I don't know how to test it.

 

Also, if it is bad, is it possible to swap in the electronic climate control?

First priority is to check the vacuum. Many of the vents and doors that change where the air comes out is regulated by vacuum. Simplest problem would be that the vacuum line from the engine is broken or has a leak. Being a 16yo car, likely that some vacuum lines have cracked. Also, I've kicked one loose with the gas pedal foot. You'll want several feet of vacuum line, a vacuum gauge and pump, lost of patience and be ready to contort and twist around the cab and engine compartment.

 

For the a/c that'd be electrical in nature. Search down old posts for that. Also, make sure you have a decent electrical diagram. The one in the Haynes manual will do.

 

Nick

I resoldered the control unit, and now the positions work but the blower is dead :-(

You can check to see if the blower is the problem by running power directly to the motor. If the motor runs ok, then check the blower relay for a problem.