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Ask GM Tech (Cam) Your Own Question
GM Tech (Cam)
GM Tech (Cam), Chevy Technician
Category: Chevy
Satisfied Customers: 29523
Experience:  GM Grand Master Technician 2007. 14 years experience.
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Chevrolet Silverado 1500 Classic LT: 03 Silverado, ac compressor

Customer Question

03 Silverado, ac compressor will not engage. With scan tool pcu is not getting a/c on signal.
Submitted: 2 years ago.
Category: Chevy
Expert:  GM Tech (Cam) replied 2 years ago.
Hi there, I am Cam. Your scan tool, does it show ANY codes at all then? Also if you bypass the relay for the AC compressor by manually jumping the pins 30 to 87 using the numbers stamped on the bottom of the relay, does the compressor engage?
Customer: replied 2 years ago.
No codes & yes the compressor will engage by jumping the pins.
Expert:  GM Tech (Cam) replied 2 years ago.
OK, if you tap on the low pressure cycling switch, or if you remove the connector and jump those, does it make the compressor run?
Customer: replied 2 years ago.
No, I have the low side cycling switch jumped.
Expert:  GM Tech (Cam) replied 2 years ago.
Does your scanner show you the high pressure reading from the sensor?
Customer: replied 2 years ago.
No it does not, when I data stream it the only a/c item I see is "a/c relay request" and the value is "no".
Expert:  GM Tech (Cam) replied 2 years ago.
OK, check the wiring around the high pressure sensor at the back of the compressor and see if there is any damage/nicks/pressure/chaffing and such.
Customer: replied 2 years ago.
I have inspected this & it looks OK.
Expert:  GM Tech (Cam) replied 2 years ago.
OK, lets try a re reset. Take the battery cables off the battery, hold the ends together for 10 seconds then attach them to the battery and see what happens. This will reset the whole vehicle.If you have 2 batteries, then remove both and touch only one set.
Customer: replied 2 years ago.
I will try that tonight, the vehicle is at home & I am at work.....will get back with you tomorrow AM.
Expert:  GM Tech (Cam) replied 2 years ago.
Sounds like a plan. Please bookmark this page so you can easily navigate back to it so we can continue the discussion. This is done by pressing (CTRL D on PC and CMD D on Mac). You can reply at any time for follow up information regarding this issue, even after you rate the site and I will reply.