On my 94 coupe the fan speed and temp control switches pretty much work when they want to.  What I mean is when trying to adjust the fan speed or temperature either up or down - most of the time I get to response from the switches.  Consistent pushing of the buttons will sometimes illicit a response, but not always.  If left alone for several minutes then trying again it will usually respond.  Does anyone have any suggestions on a fix?   Thanks

my 90 acts funky too. i have changed the head in the dash (partly cause i could just about read the digital display) and it still has a few quirks. sometimes when i start the car the a/c will activate, sometimes the defroster won't kick in. i believe there is another control unit in the dash board. if i come up with anything i'll let you know. hopefully  another member might have an answer.

on my 91 I replace the heater core #%^*$@!+!!!! and a few other words plus three days I got it all back together. Come to find out my temp.door does not work after getting no air or heat,I found out how to get the problem codes from the heater/air cond.control the code was given as a bad heater temp.door motor mulfunction.When I found out to fix or replace it I have to do the same job I just did #%^*$@!+!!!!.I talk to a gentleman at carlisle he told me if the door is sticking,hungup or the motor is bad it will not send the signal back to the controller ? he also told me to try takeing out the glove box on my model there is an air duct to move early models had the ecu there (project for spring) HOPE THIS HELP wrs