Dang a/c problem...
 

How it all started...

A few months back the air temp lever on the ol '96 XJ 'seemed' to stop working as the air temp coming out of the vents stayed the same no matter if the lever was full left or full right. My first idea was that the temp mix door had somehow become disconnected from the temp lever cable, but this was ruled out as I could hear the air temp mix door (deep in the dash) flap back and forth as the lever was moved. Seems like I remember the air vent temp being stuck on both full cold at times and on full warm at others.

Two weeks later the A/C went out altogether with the compressor not turning when the a/c was turned on. Had no clue why at that point.

Then a week later I get this loud chirping coming from what seems to be the compressor. The chirping goes on without the compressor being activated and seems to stop after about the first 5-10 mins of driving. Maybe the engine heat causes whatever to adjust and stop squeaking...don't know.

So a week or so after the chirping starts I finally figure out I have a blown 15 amp fuse under the hood, and when I replace it the a/c starts working again. This fuse continues to blow on a daily basis and when it does the a/c stops working again...

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So at this point I have an a/c that keeps blowing it's fuse, what seems to be a squeaking compressor, and a temp adjustment knob that seems to be intermittently unresponsive although the temp mix door sounds like it's working.

I'm exhausted trying to figure this out but my best guess on the temp lever deal is that it isn't the temp mix door that's malfunctioning, rather I'm guessing it's possibly this valve piece under the hood?...

https://cimg2.ibsrv.net/gimg/www.che...8346b11e53.jpg



I replaced this valve piece a few years ago because what I assume was the original valve broke open and began leaking coolant. Not sure if what I used was OEM or not.

So my questions are...what in the crap is causing this squeaking and how do I find out what keeps blowing my a/c fuse?

I'm afraid I may be facing two different issues here. When I get the fuse thing figured out (could it be this valve piece somehow blowing the fuse?) and if that stabilizes the unresponsive temp lever I'm guessing the squeaking will continue, but don't really know.

Sorry this ones so long. I'm all ears.

All that valve does it keep hot coolant from going to the heater core so your AC works more efficent. Is that thing vacuum or electrical controlled?
What year is your Jeep btw? I don't have that valve on my year but I am familier with them from another vehicle i used to own.

Check your AC clutch too. Possible your AC clutch is going out drawing too much power trying to keep the compressor engaged and popping the fuse

Thanks for the help IF. Just recently figured out the valve is vacuum controlled so it probably doesn't have anything to do with the electrical short problem. Although I'm guessing it still might be the culprit causing the loss of control of air temp. Can anybody please explain some more about how this coolant switch works in the coolant system and if it could possibly be the malfunctioning part that's causing loss of air temp control?

At this point I'm planning on changing out just the clutch to see if that solves the problems. But I've been warned that I need to make sure the compressor isn't locking up before I put on a new clutch b/c if it is it'll burn up the new clutch. How can I test to make sure my compressor isn't locking up before putting the new clutch on?

Sorry should have mentioned up front but this is a '96 XJ with inline 4.0.

Since I last posted I've been informed that the 15 amp fuse that keeps blowing goes to both the compressor clutch relay and the aux fan relay, although not to the compressor clutch or the aux fan. So, quoting, I've been given advice to...

'Replace your 15a fuse...turn a/c off...pull temp sensor connector off the temp sender in the t-stat housing...if the fan runs then its probably your a/c clutch relay...if the fan doesn't work then thats the relay thats bad'

I'm sure this is solid advice but more opinions are appreciated.

I'm going the lazy route and just bought both the clutch relay and the aux fan relay. I've replaced the clutch relay and gonna see if the fuse blows again. If it does I'll replace the aux fan relay and see what happens then. If it continues I guess we'll know neither of the relays were the problem.

Any thoughts?