A/C Suddenly Not Working
 

Hi all, I have a 98 XJ and the A/C has stopped working in it. It was running ice cold in the morning when I was driving to class and then when I left that afternoon it would no longer blow cold at all. The blower still works and so does the heat but I can't get the A/C to work at all. I've checked the compressor and it's not engaging. I've heard some nasty stories about the evaporator core going out in our XJs and how expensive they are to replace, so I'm REALLY hoping it's not that. I will probably just take it to a mechanic I trust and let him do a diagnostic on it, but I wanted to see if anyone here could give me an idea of what might be wrong first.

You're probably out of Freon. Take it to an AC shop and have them check the system pressures. They should know how to jumper the Low Pressure Cycling Switch connector to engage the compressor long enough to check the pressures.

Yeah, they typically will blow ice cold right before going out. I'm not being sarcastic here. I have experienced that myself.

Diagnostic then fix the leak. It might just be a hose or fitting under the hood. Think positive until proven otherwise.

If it is indeed the evap core I'll probably just say screw it and live without A/C then. I'm not sinking in $1000+ just to have cool air. After all it's a Jeep, and the windows do roll down :laughing:

Really? I didn't know that. I honestly thought that it was a coincident when mine got really cold when I had a o-ring go bad and I lost freon.

Don't give up on it yet. You may just have a small leak like an o-ring or something simple like Firestorm said.

Not to burst the positivity bubble going on, but I bet your evap core is shot. I have a '98--same thing. Common, unfortunately. I'm not too anxious to tear apart my dash to fix it.

It amazes me that a part like that could just randomly get a hole in it. It's made out of aluminum right? So I wouldn't think it would rust out or anything. I guess if I knew more about it, I wouldn't mind spending a day replacing the core myself and save the money, but I wouldn't want to try it by myself and unfortunately I don't know anyone around me that knows a lot about tearing into a Cherokee's dash either.

Well they don't rust. But with Freon running through it at high pressures, I can see where there could be an abrasive effect over time wearing aluminum molecules off the tubes.

Eventually a weak spot could develop and grow into a hole.

Nothing lasts forever.

The A/C system is designed to stop the compressor when Freon gets too low. Freon doesn't just cool the air, but it also lubricates so it's good compressor shuts off when it gets too low. They make synthetic Freon now that also contains stop-leak properties. My A/C did the same as yours, and I found the 2 types of Freon I just mentioned. I put them in and a/c has worked fine since. [ about 2 yrs. ago ] While you're at parts store, look at recharge kits they have. Its usually just a hose with slide fittings on ends. You'll find instructions in the kit and it's extremely easy to do. Maybe 15 minutes or less. Follow the instructions and compressor should kick back on.

I'm personally real reluctant to use stop-leak in anything, unless you have it for sale and/or are on the way to the auction.

I believe it can lead to massive, expensive problems later on.

I replaced my evap myself in my '97 as I have proper refrigeration tools to do it. The new one lasted one summer and sprung a major leak. Going to try again here soon, if it fails this time I give up. It's a major process getting it changed out so I can see why a mechanic would charge so much.

Not abrasive unless you sandblast it or something.:rofl: Just good old expansion (compressor "ON") & contraction (compressor "OFF") eventually something (a weld) gives.

Yessir, its a common defect with these welds in our evap. I'm just not sure that the replacements from the auto store are any better. We'll see when I replace mine again.

It might be better in these cases to bite the money bullet and get one from a Jeep dealer.

What brand evap core did you go with? So I know to avoid that one. lol