try the pressure switch on the condenser that was my problem

 

you got a part number for this sensor?

 

I have the same issues with my a/c. I never heard my fan run either. thanks for the great info on it.

 

I replaced both sensors. And no luck. The AC works fine on the hwy., took a trip to a near by city. 40 miles away or so. Temp was about 75F in the morning and about 85F in the afternoon. But as soon as I get into city traffic no more cold air.

 

I have had this problem for a while and come to find out that the compressor clutch itself is toast on mine. it will not even engage if I force it to. You can get a compressor with a clutch from the junk yard for around $75. The clutch does not come off the copressor so replacing that only is a no.
First before you do anything, DOES IT HAVE FREON IN THE SYSTEM?

 

I checked the temp with a laser thermometer. Temp at the vents is 34F after 10min of letting the engine idle. The clutch never did disengaged and the fan never did come on.

The temp on the high side hose was at 106F after 5min. Don't know if it's normal or not.

 

It sounds like you have either a bad orifice tube, or the system is not charged correctly. Sounds like a low charge but with air in the system. When the charge is low, the evap actually starts to ice up on a hot day causing the airflow to be blocked across the evap coil. Then you get the hot air. The ice melts after sitting, clears the coil and it's cold again until it freezes up again. Check your condensate drain and see if it's dripping water after it's been running for 1/2 hour or so. If not, and it only drips after the jeep is turned off for a while, then you have the ice build up.
Also something to consider, flush the fins to the condensor coil with a hose but don't go too high with the water pressure so you don't damage it. Many people overlook cleaning that coil. I have also seen the selector inside the heater/AC box faulty and it switches back and forth from AC to heat on it's own. But with 34 vent temp, that sounds like undercharge to me. They shouldn't be that cold. UNLESS, someone put in R-22 with a "short charge" I did this once to diagnose and leak check a vehicle and I had the vents blowing at almost 6 degrees. This is NOT recommended for a R-12 or R134a vehicle to run all the time. You will burn out your compressor and most likely do other damage.

 

Are you sure the clutch NEVER disengaged? It is suposed to go on and off while at idle. sounds like a freon issue, did you check it?

 

Quick recap of today's driving. I went drove the XJ with the AC on for about 40 miles on the hwy. A/C worked fine. I had the fan on position one and recycling air. As soon as I hit city traffic, the A/C started to blow warm air. City driving lasted for about 15 min or so. I got back on the hwy and the A/C started to blow cold air once again. I stopped to get something to eat. So I let it idle for about 10min. Warm air started to com eout the vents. The fan did come on and the compressor clutch was dis engaged. Thirty minutes later I checked for water under the jeep. Not a drop in sight.

So I drive to a friends house, so that I could borrow a set of manifold gauges..Been here for an hr or so. And Finally I saw a puddle of water under the jeep. I guess it's icing over.

Turns out that he left the gauges at work, So now I am on my way to the store to buy my own set of gauges. I'll report back later this afternoon.

thx

 

while I was sitting in the parking lot for 10min or so. The clutch NEVER did engage. The fan came on 3 times.

 

your clutch is bad...common problem, had the exact same problem...you can replace the clutch itself but the clutch new is the same price as a new compressor with a clutch

 

I rather replace a compressor then a damn evaporator.

Here are my readings with the car on...normal? ambient temp is 64F.

 

Your clutch must be engaging because you'd never have suction pressure that low if it didn't and wouldn't have that high of pressure on the high side as well. So the clutch is working. They normally get stuck where they don't work and you then have NO air conditioning. It sounds like someone charged the system without putting the system on a vacuum 1st. You could use a little charge as well. I know it's only 64 degrees ambient temp but you should have just a few pounds higher on the suction side. Has there been any work performed on the AC system recently?

 

Not sure. I picked up the XJ back on Nov of 2010. We had a colder then normal fall/winder here in central TX so I have not used the AC till now. I did see a receipt for a recharge from march of 09 from the previous owner.

But I'll go ahead and do a recharge. Should be at 35psi correct? I'll report back in a few days. I may have a leak somewhere just hope it's not the evaporator.

 

Anyone licensed can do a recharge on the system. Just know that you have a leak somewhere and will have the problem again. And just know that it is illegal to intentionally vent freon in to the atmosphere. So by charging a system that is know to leak is exactly that. (just sayin) It just depends on how bad the leak is. You should have it leak checked so you're not stuck on the hottest day of the year with no AC because THAT's when it won't work. Happens all the time. When the all leaks are found, have them repaired and make sure a vacuum is put on the system BEFORE charging. Air and moisture are the absolute worst thing for AC systems. Once you have the vacuum down to the proper micron count, leave it all connected for about 1/2 hour to make sure the pressure doesn't rise back up. Vacuum is negative pressure btw. So if the suction side goes back up to 0 you still have a leak. If it holds vacuum, then you're good to go on charging. I believe the jeeps take just under 2 lbs of 134a. But you'd need to verify that for your vehicle. Good luck.