Hello,
I started to put refrigerant in my 1998 5.2L Ram 1500 with a manifold gauge when my compressor decided to stop clicking on. I checked the fuse and relay, they are fine. Figuring that since the refrigerant was too low to engage, I jumped the low switch, still nothing. I finally jumped the battery to the clutch wire and heard a click and clutch moved very slightly, but no engagement.
Do I need to replace just the clutch or the whole compressor?
Thanks!

 

See if you are getting power and ground at the connector the clutch. Engine running, a/c on.

 

I'll borrow a multimeter tomorrow because I did not test ground. I tested continuity on positive and hooked up negative to the car battery. There was continuity then. Is your thought that although I put direct power to the clutch from the battery that if there is a ground issue that it would not have engaged?

 

Did you see what the pressure was before you put it in? Is the relay engaging when the ac is on?

 

Use some jumper wire to run power to and from the clutch. If it barely moves, or doesn't move at all, the clutch is bad. You can replace just the clutch. However, if the shaft is oily, your compressor seals are on the way out. That may be why you have to replace the refrigerant. In that case, I'd replace the whole magilla.

 

I did a lot of jumping and measuring today.
First, I do have ground in the black wire with the red clip leading to the clutch.
I also tried jumping the green low switch, the switch above the compressor that look like they lead to refrigerant lines, and the relay pin socket #30 to the pin socket above it. When I did that, there was NO continuity to the cable going into the clutch. When I jumped the relay to the battery, was able to continuity in the cable. Strange. In fact, when measuring on the jumped relay I couldn't get continuity on the jumper itself!

 

To close this one off, the AC clutch started to turn on again. I pulled a new vacuum, put in refrigerant, and had AC for first time in 8 years--for 3 glorious minutes until the clutch stopped again...

In the end, I pulled a shim from the AC clutch and it worked consistently again! I did check to make sure that the clutch wasn't actuated all the time, but thankfully it only comes on when I turn on my AC.

Thank you everyone for the suggestions!