MattArnold

I have a 2021 Silverado Custom Trail Boss and I purchased an OEM-style fog light kit from Phastek. As I started going through the install, I noticed that BCM connector X5 cavity 10 is already populated from the factory with a blue wire that has a brown stripe. According to the kit instructions, if X5 cavity 10 is empty you install a jumper wire from BCM X5 cavity 10 to UEC connector C3. In my case, there is already a factory wire in X5 cavity 10, but UEC C3 is empty, and the kit does not include any other wire that populates C3 besides the jumper. UEC B3 is also empty. The headlight switch with the fog button has not been installed yet and the BCM has not been programmed yet. My question is how the BCM communicates the fog lamp command to the UEC once fog lamps are enabled in programming if C3 remains empty. Will the BCM drive C3 internally after programming even without a physical wire present, or is the expectation that the factory wire in X5 cavity 10 should be removed and replaced with the jumper wire to C3 so the BCM can signal the UEC. I am trying to understand the correct architecture before depinning anything to avoid backfeeding or unintended lighting behavior.