I have a 2015 Tahoe whose front USB ports AND the cigarette lighter power source are dead. That screams a bad fuse but I tested every fuse in both the right and the left fuse box With a multimeter and all are good. Not sure if there is a relay that could affect operation? Does anyone know if the power cable for these is the same because it seems odd that both would fail if it’s not a fuse Could the fuse PORT be bad? Help!

 

did you visually check them or with a multimeter? the cig fuses should be something like "APO" you got to check them with a multimeter

 

@Irish_alley

 

I'm pretty sure they're on the same circuit. Take your DMM, grab a wiring diagram

http://www.bbbind.com/tsb-wiring-diagrams-database/

and start tracing backwards until you find 12V.

 

dont know how i missed that, thank joe