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Chevrolet Repair/Electric Fans Stay Running


Tim wrote at 2010-04-29 13:29:51
My 2005 Silverado, 1500, 5.3l is having the exact same two issues.  Fans running when turned off and intermittent missing/smoke/flashing check engine light.  Did the original questioner ever get the problem resolved?  The truck has been in the shop now for a week and they can not figure it out.  Can Keith be contacted by email?  

Weldon wrote at 2013-02-20 21:54:38
I just repaired an 05 sierra 4.8 that had the exact problem. The low speed fans stayed on all the time with the ignition off and went off whith the ignition on then go back on with ignition off. It was difficult to diagnose but found the problem and verified it as the problem. The ground wire for the #1 cooling fan relay grounds internally in the pcm when pcm commands it to operate the low speed fans. That dark green wire from the relay goes to pin #42 on the pcm connecter #1. when i unplugged the connecter, it had built up green corrosion in between and around the pins causing continuity between the pins next to them. I pushed on the wires that were corroded and pushed out the pins far enough to clean good. reapplied dielectric grease, reassembled and no more problems. to push wires from connecter you have to remove the plastic cover over the wires and the plastic cover with all the little holes in it on the other side of the connecter. the wire cover is a pain not to break the tabs that secure it.  

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Gary Malone


any gm car truck and van


I have been working on cars for over 15 years almost half of that at gm dealerships

ase master certified and 100% certified in several areas by gm

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