99 Xj A/C Issue! Please Help!

19Rusty73

Active Member
Joined
Sep 13, 2007
Location
Mayodan, NC
I have a 99 xj 4.0 and the A/C seems to be actin crazy. It hasnt blown cold since i got it so i charged it to the right level, still nothing. Anyways now it will come on and blow cold but it wont cycle and keep the cold air running. Plus it will only run when the vehicle is cold after sitting all night. Whne the vehicle is hot the compressor wont start at all, just blows hot air. One issue i noticed also was my A/C relay under the hood gets really hot while all this is going on. Ive had some people look at it and they cant seem to figure it out. The compressor is free and spins fine, the wires are not broke and it has a brand new relay, still no a/c and hot as hell. Any help in the right direction would be grateful. Thanks
 
Bypass the low pressure switch on the suction line. This is the line where the fill port is. Just take the connector off and jump it with a wire. If that makes the compressor run properly, change out the pressure switch. If not, you may have a problem with the high pressure cutoff inside the compressor or you may have an overcharge causing the compressor to not run.

How did you fill it to the correct level? Was the system vacuumed down prior to filling? I ask because it's easy to overfill the system and can really screw up the compressor.
 
high pressure switch

when it engine gets warm with the a/c on does the auxillary fan stay on when the ac clutch is disengaged? i found mine doing the same thing.. it turned out my high pressure switch was going bad.. when the plug got hot it would quit running. i cut the plug off the wiring and jumped the wire together and it runs just fine.. the switch is located right behind the compressor on the discharge line...just make sure you have not overcharged the system, or you'll blow the seals out of the compressor..
 
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