2012 Silverado 1500

[GabeSlaich]

I have a plug that’s not plugged in under my driver side dash coming from the headliner harness, Third brake light is not working but the cargo lamps work. The plug is a Delphi PA6-GB20 GF10, and I can not find anywhere it can plug into

[Jsdirt]

Probably for an aftermarket trailer brake controller, although its wiring shouldn't be going up into the headliner. Normally the wires are hidden in tape, and you have to cut the tape off and install the plug that comes with whatever controller you bought. That could be what it's for if you didn't buy the truck new. Those wires usually run down on the floor as far as I know. Never traced one back to see, though.

 

There's probably 10 other plugs up in there that I wouldn't have a clue about. No shortage of wiring on modern trucks, that's for sure.

[JimCost2014]

1 hour ago, GabeSlaich said:

I have a plug that’s not plugged in under my driver side dash coming from the headliner harness, Third brake light is not working but the cargo lamps work. The plug is a Delphi PA6-GB20 GF10, and I can not find anywhere it can plug into

Welcome to the site.

 

How about posting a picture? Makes the guessing easier.