1997 850R AC will not turn on

[gmolen]

Ok so this is what I did. I checked the AC relay in the glove box (blue) and it clicks when the AC is turned on. I pulled it out and checked it with power and a meter and it looked good. I don't think there is power going to the low side switch because I got no reading on it today. I tried to jump the low pressure switch and nothing happened. I disconnected the small transistor thing to the compressor and then was able to jump the low side switch but AC still was warm. I am not sure if the compressor engaged but the engine revved up and the fan went on. I am not sure I am any closer to solving this problem!
Phat

[phatjacques]

The saga continues! I noticed that the clutch had a larger gap on one side so I re-shimmed it and of course the AC still didn't work and the compressor would not turn on! The good news is that the AC relay is fine and that I was able to jump the low pressure switch and the compressor went on! I am going to get a new low pressure switch and check the refrigerant level to see if it may be low.
Phat

[jblackburn]

Think the low pressure switch may have been your culprit all along!

[gmolen]

Nearly 9 months later and when I need AC the most nothing. Took it to a shop and they did a vacuum on the system and then a leak test. Shop said that the refrigerant was leaking from the compressor and that I need a new compressor. The shop said that the leak was from the pressure relief valve in the compressor itself. I am not sure what would cause this as reading posts on AC most problems are from the clutch or low refrigerant. Probably about a 800 to 1k job. This is the 2nd compressor that has been put in the car since I bought it. First compressor worked and blew cold air and then refrigerant leaked out from the compressor as well. I am wondering if it is possible that there is a blockage in the system somewhere which is causing the leak, or if there is another problem all together. I am kind of at a crossroads with this car, I love it and want to keep it but this is driving me nuts!

[JimBee]

I posted a question about the seals leaking on my compressor. Ozark Lee commented that he has had some success stopping leaks using an AC seal conditioner, which I plan to try. The problem is during long periods of non use the seals can dry out.

AC shops aren't likely to recommend a shortcut workaround like that, but it's worth a try.

Do you have dye in your system so you can see where the refrigerant is leaking? That might help you to trace and confirm the problem.

Good luck.

[gmolen]

I do not know if there is a dye in the system as my shop did the work. I believed that they did use a dye to detect the leak. I tried to charge the system myself and what I saw was fairly obvious, hissing and whitish cloud of refrigerant coming up from under the car.

[dbooth914]

Hey phatjacques,

Please finish what you started so we can all benefit.

I am having a similar problem with my AC, and would love to hear if the low pressure switch solved your issue.

Thanks!!

[dbooth914]

FYI, I did get my AC working.

The fix was 3 part process, and I believe all 3 were contributors to the AC failure.
1) Added freon to the system. It was suggested that the low pressure switch will not close if the system is low on freon. Static pressure measure @ 60psi or so and I'm told it should be between 100 and 125. It took 12oz to get the running pressure to 35psi which is about right when the compressor runs. I had to "hot wire" the compressor to get this done.
2) The grey wire to the compressor from the low pressure switch was broken or erratic. I had 13v into the low pressure switch, but not from the switch. Jumping the connection did not power the compressor. I replaced the grey wire and the compressor came on, with the low pressure switch jumped at the connnector.
3) Replaced the "Pressostat" or Low Pressure Switch, and all is well!

HTH

--Doug