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Discussion Starter · #1 ·
This is on a 95 GL, 2.0, manual trans 130k
I've been struggling with this for about a week now and I think I finally
have the problem at least narrowed down. It seems that the a/c stops
working when the engine warms up. It's been rainy around here, so I've been using the a/c quite a bit first thing in the morning. Pull out of the drive, flip to defrost and hit the a/c. Compressor kicks on and nice coolair starts flowing. A short while later, I notice the windows start fogging quickly. No a/c. Hit the switch a couple times and the compressor isn't kicking on.
First time I ignored it. The next morning, I unplugged the wires from the compressor and then plugged them back in. Just checking for a good connection and no corrosion. I jump in the car and start it up and it works again. Cool, I think I have it fixed head out to pick my kid up from school and at just about the same point in my drive, I notice it has stopped working again. Come home, watch the kid for awhile, have dinner, etc. And head back to the garage. I find a broken ground strap between the coil packand the valve cover, so I make new one. Start the car, and the a/c works again. So I think it is fixed again! Same thing the next day. It works for 10 minutes or so and then nothing. This time I check for power at the compressor and have none. But then hours later it starts working again.
So it seems like something that controls power to the compressor is fouling up. Isn't there something that is supposed to prevent the compressor from kicking on at low ambient temps? Or I remember one of my cars used to kick off the compressor if the throttle was at wide open, to improve passing power and to keep the compressor from being spun too fast or something like that.
Don't have my Bentley yet, and for that I should be flogged, I know. It's on the list. any ideas?
Thanks.
-T.
 

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Re: a/c gremlin - an odd one (dailydriver)

If you are running low on refridgerant there is a low pressure switch that will cut the compressor off. Ambient temp will affect the system pressures. I would get the system checked to make sure it is full and the high side and low side pressures are in the correct ranges.
 

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Re: a/c gremlin - an odd one (boosted bora)

is the engine temp normal ? there should be a temp sensor on the outlet of the head with a white two pin connector... if this sensor is tripped the A/c is disabled in the event of an over heat. either your car is overheating for some reason or that sensor is bad...
 

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Re: a/c gremlin - an odd one (veedublvr)

also if the outside air temperature is below 41 degrees the a/c compressor is disabled so that the evaporator coil doesnt freeze over... more info please...
 

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Re: a/c gremlin - an odd one (veedublvr)

Quote, originally posted by veedublvr »
is the engine temp normal ? there should be a temp sensor on the outlet of the head with a white two pin connector... if this sensor is tripped the A/c is disabled in the event of an over heat. either your car is overheating for some reason or that sensor is bad...
http://****************.com/smile/emthup.gif
That's probably the case. When my temp sesnor went bad, it would randomly shut off the A/C compressor. It made for some interesting highway driving. Replace the temp sensor, it's only about a $15-$20 part.
 

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Discussion Starter · #6 ·
Re: a/c gremlin - an odd one (Glenn J)

Well, I sold the car today! The easiest way to fix the a/c was to lower the selling price!

But here's what I found, just in case someone else runs into this problem down the road.
Lot of friends kept insisting that it was low on refrig. So I decided to check the high press side with the compressor running. So I put a gauge on the hi side, and it was reading ~120 psi with the compressor not running. Then I jumped 12v. to the compressor and started watching the pressure. Pressure increased to about 200 psi, and the fans kicked on high. The additional cooling brought the press down to about 160 and the fans kicked off. The press then went to 250 psi and the fans kicked on again. Fans went off at ~200 and the pressure started climbing again, but this time the fans only ran briefly and then stopped. High side pressure went to 350 psi and that's when I chickened out and cut power to the compressor. My guess is that the expansion valve is stuck closed. When the motor is cold, the pressure in the system is low enough that the system will run for a couple of minutes. Once the pressure builds up, the system shuts down. I was going to pull the expansion valve and just try cleaning it up, but then a buyer came by today. Dropped the price $300 and she was happy. I hate that I'm not going to completely solve the problem, but I guess I'll save my knuckles for the 98 I'm picking up next weekend.

Thanks a lot for the tips and ideas.
-T.
 

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Re: a/c gremlin - an odd one (dailydriver)

Interesting. Hopefully your post will help someone out in the future.
Good luck with the new car. http://****************.com/smile/emthup.gif
 
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