I recently purchased a 93 850glt for my daughter and have been putting money into ever since. She recently had a issue with her A/c/heat controller. Seems she was driving with the heat on and heard a loud pop in the dash, some smoke came out and the heater quit working mo A/c either. After some checking the codes I found it had almost every code that had to do with the heat and a/c showed up in the trouble code storage unit. After checking all the fuses and relays and finding none bad, I started digging into the dash.

Well to make a long story short I found the source of the smoke. The bottom board in the Climate Contol unit had a Capacitor that had exploded (looks like only the one capacitor was affected on the board. Here is my issue. A new unit is $750, but I don't want to put a new unit in if the problem was caused by something external to the unit itself. From my electrical experience; usually if there is a short in a system either a fuse will go or a resister will open up. Not sure what would cause a capacitor to explode though. I need to know if there is something I should check first before hooking this new unit up? everything was working fine until the capacitor smoked. I don't want this to be a very expensive lesson, so any help would be appriciated!

Thanks Vic

 

Control module is known to go bad with age.

Also inspect the blower motor and resistor.

Alot of times when the module goes bad it will also take out the blower motor and resistor.