Hi, I just bought a 1989 Cadillac Deville and ever since the Fuel Data Center & Climate Control Center display a "C" and sometimes a "D". I haven't been able to get anything to work on them and the fan always blows. I've found out that this is a very common problem and could be fixed by replacing the Climate Control module itself or the Body Control Module. I've purchased a CCM, but I'm unsure on how to remove the old one to replace the new. I can't get it from the front and can't exactly get it from underneath. (I can only disconnect it) Before I go ripping everything apart, I'd like to hear a expert's opinion on the matter. Do I even need to replace it? Or is it something else? I also tried a diagnostic on it but it wouldn't work. Strange thing though is when we diconnected it everything started working again for just a few minutes then went back to a "D" and "C" code.

 

Mine did the same thing and had to replace BCM up behind glove box inside the car.

 

Working up under the dash is a bear. I've been there a couple of times, had to replace the heater coil which is the very worst job I ever did!

Remove the glove box, then give it another go.

I find that I usually have to remove a few other things to get to almost anything under there! Be very careful not to mess up the heater door setting, it is easily bumped and knocked off kilter.

These cars are great but they were never meant to be worked on!

Get a factory manual, it is worth its weight in gold.