A/C freezes

Randy Herd

NAXJA Forum User
98 Sport, 110,000 miles, A/C does not cycle and freezes blocking air flow. A/C shop said they have to full the dash to replace the thermostat in the heater core area. Jeep dealer said the magnetic compressor clutch is bad and needs to be replaced. Of course neither shop will guaranty their guess.

The A/C turns on and off at the dash switch. Other opions are welcome.

Thanks
 
I had both syptoms you discribed on my '98, but were somewhat unrelated. The first is the freeze up and is addressed in some TSB's. By replacing the low pressure cycling switch (TSB #24-13-99) (97-99 XJs and TJs) this prevents evaporator freeze-up and subsequent refrigerant leaks. The other (TSB #24-13-97) (97-98 XJs and TJs) points out a common leak at the AC hose manifold on the compressor. AC leaks in 97-99 XJs seem to be pretty common. My problem cropped up at about 38,000 miles.

The first to go out on me was the low pressure switch. That fixed my problems for a while, but about a year or so later I developed problems when the AC would not maintain cool once again. It would cool for about 10 - 20 minutes, then cut out. After a while, it would start to cool again, then crap out. This led me to believe that it was not the low pressure switch this time since I had no icing and the air flow stayed the same.

This time it was the clutch on the AC unit. I got that replaced at 55,000 miles and the AC has been working fine since then. This leads me to believe if your AC is still cooling, then the culprit at this point is the low pressure switch. Incidently, the AC clutch is a dealer only item. I searched everywhere for a replacement and couldn't find one. The AC clutch itself is about $200 or so, add another $250 to install and set by the dealer, unless you order the part and replace it yourself. You do not have evacuate the system to install it, but according to the mechanic, there is some sort of gap setting on it. For the price and to save me headaches, I had the dealer deal with it....

Ivan
 
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It is simple to check the compressor clutch. Simply wait until it is freezing up, open the hood and unplug the compressor control harness. If the compressor stops compressing, it is not the clutch.

Tom Houston
Loveland, Colorado
 
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