My transmission stays on third gear

2007 GMC SIERRA
100,000 MILES • 6.0L • V8 • 2WD • AUTOMATIC
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RICKY ESTEVIS
  • MEMBER
  • 1 POST
My tuck (Classic hd) works perfect when I am driving without my AC on. As soon as I turn the AC it slips and stays on third gear. And it never fails to happen. Sometimes if I turn my truck off with the AC on my truck will not turn on unless I lift my junction fuse box. I recently replaced the blower resistor and it worked for a couple of days but now it does not even blow air.
Oct 28, 2018 at 7:59 PM
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STRAILER
  • CAR REPAIR CONTRIBUTOR
  • 54,189 POSTS
Hello,

Did this problem start when you replace the resistor? We should start by running the codes. It sounds like the BCM is bad.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Please run down this guide and report back.

Cheers, Ken

Oct 30, 2018 at 12:58 PM
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