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Need help with compressor issue

caddymark on Wed August 29, 2007 6:54 PM User is offline

Year: 1988
Make: Cadillac
Model: DeVille
Engine Size: 4.5L V-8
Refrigerant Type: R134A
Country of Origin: United States

Thanks in advance for your assistance! I have a 1988 Cadillac Sedan DeVille. The car is in excellent condition and was well maintained by the previous owner before I purchased it last fall. The A/C was converted to R134A before I purchased the car, and the system cooled great. This summer we had several days of record heat. On one of these days I decided to drive the Caddy (I don't drive it much). It did not cool as well as I had remembered ... but I thought maybe it was the extreme heat. Several days later I checked it again, and it still was not cool. I could hear the compressor kicking on, but no real cooling. I called a local shop to make an appointment for a recharge/inspection of cooling system. On the way to the shop (about 25 miles), I turned on my A/C to see if perhaps highway driving would assist in the cooling process. At some point during the drive the ECON light came on my A/C, not AUTO. When I tried to turn the A/C back to AUTO (maximum cooling), it immediately shifted back to ECON. In other words, I could not turn on my AUTO (cooling) A/C. I got to the shop, and the mechanic tried to charge my system. The compressor would not come on to take the charge. He tried again and again - no compressor kicking on. I looked in the manual and learned that on the 88 DeVille the Service A/C Light will come on after turning the ignition to warn of low freon or needed service (mine started coming on at the mechanic's) and that the system will shift automatically to ECON to prevent damage to the compressor (that is what is happening now). My mechanic is not familiar with the 88 Cadillacs -- and I don't know what to do. My questions are these: 1) Is there a reset process for the compressor to kick on so that the system can be recharged and 2) how do I know if my compressor is fried or not since it won't come on? Any advice on what to do would be appreciated. I have never had a problem with this car, and I just want to make sure I repair and/or service the A/C correctly and thoroughly. Thanks again.

JJM on Wed August 29, 2007 7:11 PM User is offline

Disconnect the negative battery cable for about a minute to clear the code.

I usually charge those systems with +12V fused applied directly to the compressor clutch (NOT harness side). When charging is complete, I then disconnect the negative battery cable to clear the code.


When considering your next auto A/C purchase, please consider the site that supports you:

Chick on Wed August 29, 2007 7:18 PM User is offlineView users profile

Just to add to JJ's post, I have done "many" Caddy's of that era, and found that using the Ford Blue O tube works best. Otherwise the econ mode will kick in on cool days, very hot days, due to the different pressures R134a run at. Another way to 'fool" the computer is to add a 2K reisistor on one of the two wires on the thermistor on the low side. Never needed to do that though, the blue O tube always worked. You do have a slight or large leak (can't tell from my computer) and you should have your mechanic find and fix it before recharging..Have him check the compressor front shaft seal.....Hope this helps..

PS: By changing the O tube before recharging it, you'll have a chance to check it for "Possible" compressor failure and catching it now will save you a lot of money if it fails in the near future.....

Email: Chick


Freedoms just another word for nothing left to lose

Edited: Wed August 29, 2007 at 7:36 PM by Chick

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