First, let me say thank you all for answering so many questions before. I have been lurking here since I got my 1997 XJ last winter. But now I have a puzzle google and I can't find the answer to. So I signed up to ask my question specifically.

Here's the deal, took it in to have AC fixed. They charged the system added dye and stop leak. Blew ice cold for a couple days. Then nothing.
Took it back today. They said it was a bad relay and replaced it. When I picked it up, compressor would not engage. Technician came out and jumped the relay with a paper clip, blows ice cold, even jumped for a few seconds. His assumption is something is blowing the relay. When I wiggled the relay in the driveway the compressor kicked on for a second. But I could not repeat that. I could also jump the connections as I saw the tech do.

Where do I start testing to see what is presumably causing the relay to fail? I have a voltmeter and very modest skills.

 

First thing I'd do is pull that relay and clean the contacts in the fuse box. Can use a tiny nail file or similar.. Just be careful not to over spread the contacts.

 

First, find a real AC shop.. Any "mechanic" that puts 'stop leak' in an AC system doesn't know what they're doing.. unless their plan is to get you back again and again to make as much money off you as they can.

 

if you are going to clean the contacts-do not use a metal file. use those cheap emory board nail files.

 

You check for power going in and out of relay also grounds at relay.

 

Thanks for the suggestions guys. Fired it up this morning and AC runs just fine. So something happens when its warm apparently? I'm just guessing and will leave this to the pros.

I'll see how long it runs when I drive out to west desert today. I'm going to have to find a better shop. The only reason I used this place is because of its location.

 

After the jeep warmed up the AC stopped working. I jumped the switch near the firewall and it works.

 

Which switch are you jumpering? Relay in the PDC or one of the pressure switches?

 

Pressure switch near firewall. Just for troubleshooting purposes.

 

Get Freon and top off pressure.

 

Either that or the pressure switch has failed.

 

Pressure is good, it blows ice cold!
Spent the morning installing my cruise control. Soon I'll be rolling on cruise with ac comfort!

 

What are pressures when running ?