Cadillac Repair: a/c compressor, reputable facility, ac system

Question
compressor will not come on, i applied ground to the relay and the compressor ran, i replaced the relay however same thing happens

1990 caddillac deville

Answer
The most common fault is that you have a leak in the AC system and you need to have the leak fixed and the system recharged with freon .

In other words your AC system is most likely low on freon and needs to have some put in it. But if you don't fix the leak you will forever be adding freon.

Have a reputable facility put a set of AC gages on your AC system so he can see how much freon you lost.