DilbertJeep

Hopefully, I am posting this in the correct area. My wife's 2001 Cherokee started experiencing a/c issues. The compressor would cycle on low pressure so I assumed it had a leak. She took it to a shop and the technician checked with dye etc and found no leak. I drove it and the a/c seemed to work 'ok' but not as well as it should. After about 10 minutes the air started warming up. Now, it's not cycling on low pressure. It just shuts off. After about 20 minutes or so it will start and run again and do the same thing. All I had was a cheapie low pressure gauge and it showed to be running a bit low on pressure. Not to the point where it would cycle on low pressure but definitely lower than normal. At start up it would run around 32 lbs and would creep down to about 28. I finally was able to get a manifold gauge set and check the high as well. I had wondered if it was maybe a restriction causing it to pump down and cycle on low pressure. If you put a little extra charge in, it would stay above the suction pressure cut off point but the high pressure would creep up and cycle off on the high pressure cut off point. Well, looking at the high pressure, it never got about 275 lbs. Note that this was an R22 gauge and I was converting to R134a via temperature pressure chart. It definitely has no leak, I know that for sure. I'm at a loss. Hopefuly I explained this without too much confusion. Any help would be appreciated.

Jason248

I dont know much about the a/c systems in these becasue ive not had aproblem with mine yet. Most systems have one or two cycling switchs usually mounted right on the lines, if one is going bad it could cause this. When i worked at ford i always kept one for each line in my box so i could just swap them out and check fast. but there are procedures in the service manual that the tech could have used to check them and probably should have.

This might sound stupid because i dont know if jeep offered one in an XJ but does it have an electronic Automatic Temperature Control unit?

DilbertJeep

Actually, a little update. I just went back out to see if it had reset and would run again. It had and the pressures were as follows-low pressure was running at 38 lbs and the high pressure is cycling between 250 and 325. These are both being read on an R22 gauge set. I currently cannot find a good conversion chart or anything. The high pressure isnt cycling fast, but is definitely cycling in a steady rythym.

DilbertJeep

No, just the standard dial type where you select standard, max/recirculate and the adjustable blower speeds. It's weird in that if you put the nameplate charge in, it will cycle on low pressure switch. Squeeze a tad more in to keep it above that low pressure point and it runs for a bit but will cycle off and stay off for a while. That is what made me wonder if it was a restriction and would then cycle off and stay off on high pressure. But the pressures equalize on the gauges pretty quickly so I would think the high pressure switch isnt keeping it off. This is the part that is confusing me. I had basically assumed the orifice tube was semi plugged. It wasnt a total restriction but enough to cause a problem. I know a bit about a standard home HVAC system, used to work in that business a few years ago. But auto is obviously different stuff.