Thanks for talking to your friend. That's kind of what I figured, it should be ready to go as far as brakes and lights. Those wires in the pictures near the fender well are only for installing an aftermarket controller, they lead back to the stub wires under the dash. The wire in my truck is actually labeled aftermarket. Yes, you do have to activate the circuit for trailer charging and interior lighting, I guess they don't want 12 volts dangling around if you're not going to use it.
Since the truck is still under warranty I'll have to go back to Chevy to have them check the ITBC. It could just be moisture in the connectors but there is also a pressure transducer on the master cylinder that senses braking demand. The integrated controller also takes imput from the ABS system and I've gotten some error messages on the monthly reports via OnStar about ABS faults, so who knows, a wheel speed sensor could be bad or anything. It also continuously shows error messages on the dashboard display about low tire pressure even though I keep them at 50 psi when unloaded. I guess it wants you to run them at 65-70 psi all the time. Thanks again for all the info.
