I have a 2018 Tahoe with the integrated trailer brake controller included with the tow package. I have power to all 7 of my pin connectors except the trailer brake. I have replaced the dash controller and the trailer brake module behind the spare tire.

sometimes I get the “service trailer brake” message after plugging in the 7-pin connector (only when plugged in) and sometimes there is no message. Either way, I never have power.

I have confirmed 12v power with the ground on the connector so it appears the connector is grounded. Even if I start chasing wires, I’m not sure whether to chase the power wires or the data control wires.

I have also checked the fuses as well. Not sure what the next step is other than taking it into the dealership for them to play with for a few days or bypassing everything and running my own aftermarket brake controller, new blue wire to connector, etc.