Air Conditioning

I have a 1998 Sable with Auto Climate Control.
A/C Compressor clutch relay will not pull in. Replaced relay still no good. Jumpered out the relay and the clutch pulled in.
Problem is either with the pressure switches or climate control module.
I have a volt meter but I don't know what type of signals to look for.

Haynes manual does not help.

Thanks in advance for info.

Todd

How about your refrigerant charge? If it's low it won't allow the clutch to engage but when you "jump" the relay and it will engage.

Yes, I recharged it because I thought that was the problem originally.