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Fog diode mod causing BCM SHORT and no warranty coverage

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Yes, that notation will be with you forever.

Unless it was a completed Warranty repair, it won't be available to any other dealer. Our store has no way of knowing what some other shop has done to a vehicle except to look warranty repair history.

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I took out my diode after reading this post and the potential for other issues. I'm about to run out on my 3 year 36k b2b so I'm just playing it safe

Edited by 20Bowtie14
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Unless it was a completed Warranty repair, it won't be available to any other dealer. Our store has no way of knowing what some other shop has done to a vehicle except to look warranty repair history.

If the vehicle was submitted, examined, evaluated and denied as a warranty repair it should still be in the system as part of the warranty repair history - if for nothing else so the dealer can get reimbursed by GM for the amount of time expended.


There's no longer a choice for self or independent repair. Since the new BCM must be reprogrammed to make it play nice with the rest of the modules on the vehicle's network, it has to go to some Chevy dealer for repair. Might try another dealer on the chance the invalidation of the warranty was not in the system.

Edited by Thomcat
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  • 6 years later...

For this mod to be done safely you really need to use two diodes. One like all the instructions say and a second one between where the diode connects to the fog relay trigger wire and the BCM to keep power from back feeding into the BCM when the high beams are feeding it power. I bought a X5 (brown) BCM jumper so I wouldn't affect the factory wiring that if I ever had a problem I could remove it from the system without leaving any evidence behind. 

Screenshot 2023-03-11 at 4.19.47 PM.png

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