O-K, now bear with me. I've got a '90 1/2. Air worked fine, but the interior lights and the back lights in the dash didn't. I replaced the light sensor and the BCM. Interior and dash lights still didn't work, AND now the air didn't work either, AND the odometer showed 100k more than it did before. (187,000 miles). Yeah I forgot to change the prom.
Since nothing really got fixed, I decided to put the old BCM back in. The air conditioner still doesn't work. (But it did work before). The air compressor won't kick in. Any Ideas?
I am assuming that you don't have a shop manual? There is a means whereby you can activate the A/C clutch relay to see if the clutch will pull in to trouble shoot the system. The relay in mine went bad. Using the computer diagnostics, I commanded the relay to cycle on and off. Then I went under the hood. I could hear the relay clicking, but the clutch didn't pull in. Measuring the voltage going to the clutch and there was none. The relay would engage, but the contacts were gone. $8 relay took care of the problem, but you really need to use the diagnostics to find your problem as there may be other issues?