AC Compressor Clutch not engaging

Looking for a little help please. The AC Compressor Clutch is not actuating. I tried putting in a different relay and it didn’t work. I tried taking the relay out and jumping it by connecting the 87 and 30 terminals and that didn’t work. Then I connected directly to the coil on the compressor and the positive terminal on the battery and the clutch did actuate. So at least I know the clutch is operational. Now I am trying to figure out why it isn’t actuating when triggered. Any tips on where to look next? Thank you!

If the AC system is low on refrigerant. the compressor clutch won’t engage.

Tester

Thanks for the quick reply! Shouldn’t the clutch actuate, regardless of refrigerant levels, when the 87 and 30 terminals are manually connected?

There’s a pressure switch in the system that prevents the compressor from damage due to low refrigerant.

Tester

Do you have 12 volts in cavity 87 of the relay box?

Yeah like tester said. Somewhere on the metal line there is a pressure sensor with a couple wires going to it. I have had a bad one before so the clutch wouldn’t engage. Or could be low on refrigerant. At least you know the clutch works. Might be a fuse in there someplace too.

Inserting a jumper wire into the relay socket bypasses the low-pressure cut-out switch. If bypassing the relay does not engage the clutch, the low-pressure cut-out switch is not the problem.