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  #1  
Old May 27th, 2010, 19:00
oldbill oldbill is offline
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Angry 2000 Jeep Cherokee Flakey Air Conditioning

Just started this year on my wife's Cherokee. Air conditioner will start out blowing nice and cold, then after sometime, the air coming out will see to be almost outside temperature. After awhile it is blowing nice and cold again. Doesn't happen all the time, nor is there any frequency to the cold / warm cycle, or how long it last. Open for any and all ideas. I've picked up a can of R-134 and connector, but thought I'd wait until I got some feed back before going the add R-134 route.

Thanks,
Bill
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  #2  
Old June 1st, 2010, 15:03
Mudshack Mudshack is offline
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Re: 2000 Jeep Cherokee Flakey Air Conditioning

Get a connector with a guage on it. Mine does the same thing. Sometimes it is very low on R-134a and other times it is WAY high. I can't tell what triggers the fluctuation. All I know is...I get about 10min of A/C then it is gone each day until the Jeep sits for a while.

I am starting to wonder if it has something to do with how hot the engine is running. Even though it isn't over 200degrees, I wonder if there is an emergency cut off valve or something.
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  #3  
Old June 1st, 2010, 15:43
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winterbeater winterbeater is offline
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Re: 2000 Jeep Cherokee Flakey Air Conditioning

Seems like this usually will be one of two things.

1.) Compressor clutch not engaging. Easy enough to tell. The failure mode is that the gap is incorrect. While running, you can hear the clutch click in and out. If the inside part of the clutch (connected to the compressor shaft) is not turning when the clutch clicks in, you can adjust the gap.

2.) The other thing is evaporator freeze up. In humid air, the evaporator can turn into an ice ball and not pass air through. When you turn it all off, the ice ball melts. A lot of water will drip out through the HVAC housing drain.

Things people do can aggravate evap freeze up. You need to keep the airflow over the evaporator high and limit humid air getting to it. Many smokers like to keep a window partly down to get rid of smoke. This lets in extra hot humid air. Others may leave the temp on full cold and turn down the fan when it gets cold in the car. Lack of airflow.
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  #4  
Old June 1st, 2010, 15:48
Mudshack Mudshack is offline
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Re: 2000 Jeep Cherokee Flakey Air Conditioning

winterbeater......I think that my problem is #2. What do you suggest doing? It is not that humid here in Kansas City. But I did notice a lot of draining the other day after it sat for a while. And this would explain why it stops blowing after it runs for a while. And would explain the high psi. How do you keep it from freezing?
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  #5  
Old June 1st, 2010, 16:41
joe_peters joe_peters is offline
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Re: 2000 Jeep Cherokee Flakey Air Conditioning

Not that familiar with the 2000 heat/air box setup, could be a blend door issue.
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  #6  
Old June 1st, 2010, 22:14
RCP Phx RCP Phx is offline
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Re: 2000 Jeep Cherokee Flakey Air Conditioning

Quote:
Originally Posted by joe_peters View Post
Not that familiar with the 2000 heat/air box setup, could be a blend door issue.
x2,have you checked the vacumn controls?
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  #7  
Old June 2nd, 2010, 07:01
Mudshack Mudshack is offline
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Re: 2000 Jeep Cherokee Flakey Air Conditioning

Now that I released the pressure, the pressure builds to about 60psi, the unit kicks itself on, the psi then rapidly drops to 15psi before the A/C unit kicks off. Now it acts like there isn't enough coolant in it. I am starting to think that with the right amount of coolant in the unit, it runs for a few minutes (producing cold air) an then it must freeze up somewhere. When it does the psi goes up through 80- 100psi which is where it was at when I started releaving pressure yesterday. What would be causing the unit to freeze up and how can I prevent it from freezing?
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  #8  
Old June 2nd, 2010, 10:38
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xj_mike xj_mike is offline
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Re: 2000 Jeep Cherokee Flakey Air Conditioning

I had the same problem as the OP. After a bunch of reseach and checking in the FSM, I decided to pull the clutch off and removed the shim that was there. Bascially with almost 100,000 miles on things, there was enough wear on the clutch it wasn't locking up completely. I removed the shim and the A/C works perfectly!!! Nice and cold, no issues and has been that way for 2+ years now.

Personally I would not be messing with pressures, charge levels, etc. unless you know EXACTLY what you are doing and have the right tools to check things.

In my case it was "try the simple thing first" and within a half hour, things were working perfectly again. YMMV
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  #9  
Old June 2nd, 2010, 11:19
Mudshack Mudshack is offline
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Re: 2000 Jeep Cherokee Flakey Air Conditioning

xj_mike. That is the best advice I have seen in over 2 years of wrestling with this thing. It does have 165000 miles on it, and that would explain why it was up around 100psi with the compressor running and no ice.
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  #10  
Old November 24th, 2010, 12:10
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Grono-xj Grono-xj is offline
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Re: 2000 Jeep Cherokee Flakey Air Conditioning

Hello Mike:

I had the same trouble with the HVAC system of my Cherokee Classic.

I haven't to much mechanical expertise, and after reading A/C System Manual, I only found the "clutch" of the compressor.

You are talking about it or other clutch?

Sheers from Chile


Quote:
Originally Posted by xj_mike View Post
I had the same problem as the OP. After a bunch of reseach and checking in the FSM, I decided to pull the clutch off and removed the shim that was there. Bascially with almost 100,000 miles on things, there was enough wear on the clutch it wasn't locking up completely. I removed the shim and the A/C works perfectly!!! Nice and cold, no issues and has been that way for 2+ years now.

Personally I would not be messing with pressures, charge levels, etc. unless you know EXACTLY what you are doing and have the right tools to check things.

In my case it was "try the simple thing first" and within a half hour, things were working perfectly again. YMMV
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