Truck Powers Trailer

[GaryRudolph]

I just noticed that if I have the lights/brakes plugged into the truck the 12V circuit in the camper works (even with the battery disconnect disconnected). Is this normal and as designed? Will it charge the trailer batteries as well?

I'm a little surprised as it also powered the trailer with the truck off. Could have drained the truck battery on me...

[mhartzel]

Yes, there is a terminal in the 7-pin RV plug that draws power from the TV. This is by design to assist in charging the batteries and also supply power to any lights that can assist in hitching, backing or other "seeing" needs while hitched.

[GaryRudolph]

Good to know and I'll just have to be careful to unplug the trailer brakes when parked for any duration (i.e. overnight) as I don't want it drawing down the truck batteries as well.

[LadyWindrider]

Depending on the truck, most newer ones have a relay that connects the truck and trailer, only when the truck is running, or the key is on. It prevents that very thing, discharging the truck and camper battery while connected, and the truck not running. Might be time to dig out the truck manual and do some reading.