01XJ: A/C Not Working - Advice?

[cshontz]

So I just (for the time being) decided not to sell it, and this is how it re-pays me?

I'm driving home from work this evening, and 10 minutes into the drive I'm thinking, "Shouldn't cool air coming out of the vents by now?" - Sure enough, no A/C.

• Vents blow strong.
• Temperature control can produce hot and warm, but not cold.
• Different modes change correctly. (lever actuates)
• Relay not heard.
• A/C compressor clutch doesn't engage.
• Underhood fuse good.
• Last time I drove and used A/C, it hissed when turned off.

I only have a screwdriver, a wrench, a flashlight, and I don't have much experience with A/C systems. I searched NAXJA and JF without much luck for easy do-it-yourselfers. Any suggestions?

Why do I see myself trading my Miata for Cherokee service?

[madizell]

Check the relay first, as it is usually easiest to replace. Pull the relay, activate it with 12V, and verify continuity on the high tension side. Pin check the relay plug in to verify that there is a signal to the relay when the AC is turned on. If there is a signal and the relay is good, but the clutch does not engage, it could be a wiring issue, but more likely it is a refrigerant issue. Take it to a shop and have the AC evacuated and reloaded, and check for high or low pressure switches in the AC system that may have failed. If the refrigerant load is not within a specified range, the AC system will not operate to save the compressor from running without lubrication, at least on more modern systems.

[ExpoMike]

Well, it could be good news or bad. I have read a number of reports on different forums about '99-'01 Cherokees and Grand Cherokees having issues with evap unit in the dash. Apparently when they were manufactured, the "acid" used to clean the parts prior to brazing the tubes together is not cleaned out completely and over time, will eat away at the evap core and cause a pinhole leak. When that happens, you are SOL as the unit has to be replaced and the system recharged. The major suck part is, to replace the evap core you must remove the complete dash. I have heard dealers charge $800-$1000 to do this.

I have also read about people (me included) where the airgap for the compressor clutch becomes out of spec due to wear and the compressor tries to engage but does not have enough force to do so. There is a shim on the shaft that the clutch attaches to, which when removed will allow the clutch to sit that few hundreds closer and in turn engage correct. I just did this on my '00 as I was having the issue of it working okay for 10-20 minutes, then stop working for 5-10 minutes, then work again, continuing this cycling method. Took me about a half hour to do this "fix" and tested it this past weekend by doing a desert trip where the A/C was used continuously for hours. It got darn cold inside, even with the outside temp over 100*.

Typically there are failsafes built in to the system so if you don't have enough or any refridgerent, it will not allow the compressor to cycle to prevent damage to it and the rest of the system. If you have the A/C on full and look under the hood and never see the compressor clutch try to cycle, assuming the fuses are okay, most likely there is a refrigderent issue. I have also heard about the low pressure switch going bad and preventing the system to work.

If you don't have the Factory Service Manual to help you troubleshoot this or have some A/C test equipment, sorry to say a trip to an A/C repair shop is in order. A/C systems are one of those very few home mechanics can typically work on... at least correctly.

Good luck and hope that helps troubleshoot a little.

[kcowyo]

Sell it.
.

[Purple People Eater]

Sell it.
.

Don't sell it. Love it. Love it, and it will love you back. It just wants some attention. When you get the A/C fixed (which I hope is going to be easy and inexpensive), buy it something nice, and spend some quality time with it.

Regain the love, Mr. Shontz.



I'll bet it would love a nice new set of WARN sliders.


.

[cshontz]

Thanks for the advice, guys! (except you, KC - you're evil)

"Love. You can know all the math in the ‘Verse, but take a boat in the air you don’t love, she’ll shake you off just as sure as the turning of worlds. Love keeps her in the air when she oughta fall down, tells ya she’s hurtin’ ‘fore she keens. Makes her home."

[troy]

Last year I had the make the decision to repair the A/C in my XJ. My problem was due to 200K miles and a worn out A/C compressor. The kicker is that manufacturers typically won't warranty the compressor unless the evaporator core is replaced.

I went to local mechanic that I trust and it was just under $700 if I remember correctly. $500 for parts and refrigerant, and the rest was labor. It is cheaper than a new car payment and you likely won't have to fix it again for as long as you choose to own it. It also helps resale value to show reciepts for A/C work.

I do all my own work on vehicles and will do minor A/C trouble shooting, but some things are best left to people with the correct tools.

Fix it and keep it!

[grahamfitter]

There isn't one real constructive idea in this post but that's never stopped me in the past...

My Jeep doesn't have AC to begin with but when the AC failed in my VW Westy I just removed the belt and opened the windows. This solution is quick and cheap but it does expose the next weakest link in the chain: the loudspeakers for the radio.

Alternatively, on the grounds that it is always better to put off doing something that you could do today, if you can wait until this weekend, the summer will be officially over and you won't have to worry about AC until Memorial Day.

Good luck!

Cheers,
Graham

[madizell]

Going without AC depends on where you live. When it is 114 in Phoenix and the road temperatures are around 165, driving with the windows open won't cut it.

On the other hand, living in Prescott at 6,000 feet, I have 3 vehicles without AC, and can survive in any of them, as long as I stay out of Phoenix.

If the evap unit in the dash is leaking, you really have to have specialized equipment to detect the leak, and as mentioned, pulling the unit is a bear. Ancillary repairs are possible with AC, but if the core system needs fixing, take it to a professional.

[Starscream]

Chris- You're not alone.... Mike and I deal with that problem everyday one the way to work (when it is his week to drive). His a/c works for about the first 10-15 minutes, then goes dead. I'm glad the temperatures are getting cooler now.