1994 Cadillac DeVille Q&A
1994 Cadillac DeVille Question: AC and cooling fans won't work
I am assuming that the cooling fans are operating correctly when the engine temperature warrants there operation. The cooling fans will not run with the A/C until the A/C pressure builds to the point where they are necessary, with the compressor not operating the fans are not necessary. There are several things that need to happen for the A/C compressor to turn on. As I recall, the a/c control head sends out a compressor request signal through the various switches which returns to the a/c programmer. If everything is ok to that point the programmer will send an a/c request signal to the powertrain control module and if the pcm says ok a signal is sent to the a/c compressor relay which sends power to the compressor clutch and with a proper ground circuit from the clutch it will engage and the compressor will run. There is no way to diagnose this system with out a wiring diagram. A scan tool would also be vary helpful. Try www.autozone.com, they may have the wiring diagram you need. - Russ
AC compressor and fan motor is working but air will not blow thru the vents. It was recently working fine and cooling and now will not blow thru vents.