low pressure cut off switch on ac

Has anyone ever changed the low pressure cut off switch on a 98 xj. Any hints would be great like do you have to drain your system to put it on. Has anyone put one on and it not help. My ac has quit I checked freon and its running about 60 lbs and its 95 degrees out today. I can jump the low pressure switch and it works. The guy at o-rileys told me my condensor was pluged, how do I now. I washed cooling fins out ,even took the grill off so I could get to it, still nothing. HELP!!

Sounds like you need a new low-side pressure switch. You shouldn't have to discharge the system to change it.

anony91xj said:

Sounds like you need a new low-side pressure switch. You shouldn't have to discharge the system to change it.

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Watchout if it's not a factory setup. They sometimes don't have a schraeder valve under the sensor.

How do I know, it looks factory to me.

A few years back, I helped a friend diagnose his A/C and went to change the low pressure switch. I assumed it had a shraeder valve under the sensor as described by the FSM and proceeded to unscrew it. It started leaking and pushed the o-ring out so it would not reseal upon tightening. This resulted in a messy dump of his freon charge in the parking lot.

After a seriously dirty look, he later mentioned that the a/c was installed by the dealer as an add-on. They obviously did not use oem parts as the lack of a shraeder valve wasn't the only thing different. I also noticed it didn't have the normal spring loaded sepentine belt tensioner.

As for how to tell if it's factory installed? I guess if your the original owner and you're sure the dealer didn't install it as an add-on, I guess its a safe assumption that its oem.

Didn't AC come standard on all XJ's? This would mean he has a VERY good chance of it being factory original.

Not 100% that is was standard though-

Should my 98 factory ac have a schrader valve under the switch and how do I go about removing the switch, what I mean is it looks like a wrench would be use but it also looks like maybe there are two spots to put a wrench.

SCW said:

Didn't AC come standard on all XJ's? This would mean he has a VERY good chance of it being factory original.

Not 100% that is was standard though-

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Surely you jest. AC was NOT standard on XJ's, particularly in the early years.

It MAY have become standard by the late 1990's, but, like most cars of their era, AC was considered a 'luxury' option, and NOT a standard feature.

Mine screwed right off and on. 2 minute fix.

I had to change mine because it was either cold or not blowing any air, because the evaporator would freeze up.

Now, it runs cool all the time. Just cool. Not, cold. Barely cool when idling for any length of time.

when screwing the switch off will I loose my freon and what didi you screw it off with.

"IF" you jump the low pressure switch & the AC then works that would indicate you are low on freon.

BillyBob said:

"IF" you jump the low pressure switch & the AC then works that would indicate you are low on freon.

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This is not cast in concrete true. I've seen defective low pressure switches. The switch would open on low pressure but not close when the pressure rose back up. Also seen them erratic, open at one pressure and the next time it opens at a different pressure or closes at a different pressure.

I,ve checked freon in my rig it shows to have about 60 lbs. I charged it up to high to start with and I had to drain it back down, so I dont think its a freon problem.