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Neg wire to air conditioner fuse not sending signal so compressor won't start

(2002 GMC Safari)
in Blaine, WA on November 01, 2016
Can jump the negative wire and compressor starts. But can't leave the jump as it would drain power when off..
I've heard there has been problems with wiring harness corroding and wires breaking. Do I need whole harness replaced? CPU?
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Popular Answer
of Axton Automotive on November 01, 2016
The negative wire goes directly to ground. power is controlled by a relay. There is no way to drain battery by adding ground as there would be no power to the relay with the ignition switch off. are you adding power? Also you do not want your compressor continually engaged as it will over pressurize the system.
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on November 01, 2016
.I've been fighting this for awhile I bought Van used..A/C was working intermittently then I noticed the pulley stopped engaging...first I had the system recharged it had no noticeable leaks and it worked for a week then it slowly stopped engaging..Took it back they recharged it again it worked for a week..slowly took longer and longer for pulley to engage then it stopped..took it back and again no signification pressure loss.The a/c guy said it was the a/c enable fuse that wasn't grounded..Might be CPU problem?? So he jumped it and pulley engaged it worked so he found the ground wire in the harness under fuse box..cut it high and reconnected in lower and it worked for a week...then it stopped??? .I will try to replace both relays tomorrow...if that doesn't work I'm stumped..I read they have electrical issues and thought I'd try this..Before I go out looking for parts I don't know if I really Thank you for responding to this problem!
of Axton Automotive on November 02, 2016
There are no grounds going to the fuse box. What he most likely did was give power to the a/c clutch. The guy sounds like a hack that chopped into your wire harness. Your vehicle needs proper diagnosis.
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