AC Problem in Jeep Grand Cherokee
 

I've got a 93 Jeep Grand Cherokee Limited, and within the last week, I've come accross a really strange problem.

Basically, the AC decides to randomly come on.. sometimes for a few minutes... others for a few seconds... and then shut back down completely. At first, I thought my fiance might have turned it on when she was driving, but all the knobs are definately pointing to off.

I'm personally chalking it up to possibly a short in the wireing, or possibly a glitch in the computer. Would like to get some ideas if anyone has seen this before, or has any advice on what to look for before I try to tackle this myself.

Thanks in advance.

I'm gonna go with a short in the wiring...somewhere. Possibly in the switch itself. Actually, that's the first place I'd look. I don't think that anything in the compressor ass'y would cause this, and it's almost a long shot that the wiring itself would cause this exact problem, I'd think. Check the switches.

Actually...hold up...does the sporadicness only happen with the switch in the on position, or also in the off position?

Actually, it hasn't been in the ON position for months... there's a leak somewhere, and we can't keep freon in it for more than a day or so... so we just never use the AC. If it were in the ON position (or Auto actually), I'm aware that it would automatically go on and off as needed. Definately not the case.

Actually, that wasn't the reason that I asked, but you answered the question anyways. Part of the problem MAY be due to the leak, and triggering the high/low pressure switch for whatever reason...it really shouldn't but, you never know. I'd still look at the controls in the dash.

Try unpluging the wires at the pressure switch, that should stop It.

I'll go ahead and give that a try... thanks for the tip!

Jeeps have a ac compressor relay, they have been known to stick in theon position, check that relay it will be labeled it is in the power distribution center.
You can pull the ac fuse will stop this problem

yep, I second what mike said. Relays can be obnoxious as hell. Any time a high-draw device in my car goes weird, I go straight to the relay and 90% of the time that's the problem.

If I understand it right, though, that won't tell him anything. Just because you pull the fuse/relay/control module...at that point, it isn't going to operate at all. To properly diagnose this, it's got to be functional. That's why I'm thinking controls or possibly a high/low pressure switch.

To LutherMac: if you're constantly recharging the system, do yourself a favor and get this vehicle converted to R-134A refrigerant if you haven't already. And, find that leak. Any good shop will have A/C system dye, and can run that through and find where the leak is. Good luck...please keep us posted.

What he was saying is that he never uses the AC so as a temp fix to keep the compressor from coming on this would be the quickest fix. (pulling the fuse)

Actually, I've only gotten refrigerant added once (already converted ti R-134A, thank goodness)... and they did add the dye to it. I just can't afford to get the repairs done at this time.

This weekend, while its parked, I'm going to try to check the relay switch, as well as the controls on the dash. If I can't figure it out on my own before Monday, I'll just go ahead and pull the fuse as many of you have suggested.

I'll keep ya'll informed! Thanks for all the suggestions!

Jeep AC 2003
 

Actually, mine is doing the same thing and has been getting worse.
The shop just told me it is in the computer or electrical and doubt it is in the wiring but they don't have the tools to detect the problem.
Originally, it never worked unless the knob was on the "recirculation" icon which I thought was stupid, but it worked and then the light on the AC button would turn itself off. (overload or drawing too much amps?). I shut it all off then turned it to "Recirculation" and THEN hit the AC button and it started working.
Anyhow, Let me know what you've found.

Do you have climate control or just the speed/duct/temp basic system?

When you say the AC comes on, do you mean you get a fan or just that the compressor kicks in?

Assuming you have the basic system and you just mean the clutch is engaging, the compressor needs at least these before it will engage:

- Dash a/c button on
- Duct/off dial not off.
- Accumulator pressure switch closed. (low charge will prevent this, unless it's failed closed)

All three have to be "on", or any one can be off to disable the compressor. If your dash controls are forkled I'd just unplug the pressure switch connector from the top of the accumulator. Cover the ends so junk doesn't contaminate the contacts. (or pull the fuse, as mentioned, once you find the culprit)

Edit: Didn't the 93's have R134a from the factory?