‘21 Sierra - No constant 12v on 7 pin harness

[Phildosaurus]

2021 Sierra - I’m adding some LED light strips in the bed and just discovered that the 12v at the trailer harness isn’t constant, so now I need another source. Any other constant 12v nearby?

 

I’ve searched forums with little success and only found a single reference that the circuit may not be active unless a load is detected (which the LEDs do not trigger). Is this true? Any way to bypass? I’ve had trucks before that required an extra step to activate the 12v hot in the 7 pin - could that be the case instead?

 

thanks!

[EddDe]

I have a 2020 Silverado and I thought the same about the 12v trailer battery pin only being triggered by something, but found the fuse was blown for that circuit #63 in engine compartment. Once replaced, 12v is constant, even when trailer harness plug is not connected. I had to pull fuse out to see that it was blown.

[Phildosaurus]

Thanks so much, mine was blown too.

Looked ok from above and has no reason to be blown, considering that the truck has never had anything attached to the trailer harness. But an easy fix, nonetheless.