DWeikert wrote:
There's nothing stock on your truck to isolate the truck and camper batteries.
Ditto.
GM does not install any sort of isolation device to cut off power to the trailer plug or camper wiring when the truck is not running.
Sometimes a camper dealer will install one when a person buys a new camper and has the dealer get the truck ready for the camper, in the form of a large solenoid.
The way to test your truck is with a test light or voltmeter. Check for 12 volts on the battery charge line when the truck isn't running. If there's no 12v there with the truck off, but is when the truck is running, this would seem to indicate there's a solenoid.
If there IS 12v when the truck is NOT running, then there's no solenoid, or the solenoid is stuck in the ON position.
