Greetings,

On my 2005 Ram 3500 the seven post factory installed trailer wiring harness has a pin for charging the trailer battery. This pin is "hot" even with the ignition off.

Does anyone know if there is something in the truck that would prevent the trailer battery from draining the truck battery while using the trailer battery camping without any hookups? I have heard taht an "isolator" in the truck wiring would prevent this, but do not know how to go about testing if the truck already has one.

Thanks.

 

No isolator that I know of in the truck.
If your hot with key off it doesn't have one.

 

I wonder if the "trailer battery charge" is looped into the "load shedding" program where the lights turn off after a few minutes.

The power outlets (cigarette lighters) are NOT in this program and I imagine the hazard flashers wouldn't be either (although since they turn on and off, this may not be perceived as a constant drain).

Does anyone have any ideas how I might test this circuit or how I could get an answer out of Dodge?

The local Dodge dealer was no help in that he says the trailer converter takes care of this problem. Well, I know that's wrong. Perhaps he was thinking of the trailer power distribution center, but I don't think that does it either.I thought this problem needed to be taken care of via the tow vehicle's wiring.

 

Well, mine's a 2003, but the wire comes straight from the battery terminal. There is an inline fuse right near the battery that you could pull out. Or just unplug the trailer wire while you're parked.