I'm not so sure about the battery problem. Truthfully I experienced something similar in my 07 when i first installed my original iPod interface with the factory radio. My dash went blank, no lights, mirrors, ect... Anyway it was diagnosed by my local shop, had them pull that interface and replace it with my current one, no problem since. So, not sure about what you have added to your truck, but if this is a new radio with an on-star replacement interface, or a factory radio ipod interface it may be worth the phone call. Check with the dealership, many times if they find the fault in the aftermarket goods, they will make you responsible for the diagnossis and repairs (removal of the aftermarket goods).