Camper Backwashing Power Into Vehicle

[jentrxm]

We just bought our first camper ever, and an issue popped up that I'm hoping you all can shed some light on (Google failed me).

We bought a pull behind camper at a Camping World location and had them install a brake controller in our 2007 Jeep Grand Cherokee tow vehicle.

We very quickly discovered that the radio and 12v outlet in the Jeep were running even with the ignition off and the keys in my hand. A CW tech disconnected the car battery to unhook the brake controller wires, but after he unhooked the battery the power was still on inside the vehicle.

We figured out that power was flowing backwards through the 7 pin connector and it was the camper battery powering everything inside the Jeep.

The CW tech claimed the problem must be with the Jeep, but I don't trust them.

Has anyone else ever seen a problem like this? I'm wondering if the trailer is wired wrong.

[CA_Traveler]

jentrxm wrote:
Thanks everyone! Glad to know it's normal and not some crazy wiring issue.

Normal but not desirable unless you want to unplug/plug all the time.

One simple solution is a relay in the Jeep charge line that is activated by the ignition. Don't let the same tech near your equipment.

[jentrxm]

Thanks everyone! Glad to know it's normal and not some crazy wiring issue.

[time2roll]

Normal. If it bugs you, just unplug.

[K_Charles]

When you plugged the trailer into the jeep one of the wires is used to charge the trailer battery with the jeep alternator. That line hooked the two battery together. Unplug the cord when you shut off the jeep.

[BFL13]

Chev trucks have the #4 pin on the 7-pin always live, truck engine on or not. Fords have a relay so it is only live with the truck engine on. Dodge-- no idea.

[Harvard]

Research the functionality of a "BIRD" module. It is used to have the vehicle battery and the RV battery live together.
BIRD Module

[jentrxm]

Chris pretend I'm an idiot.

[Chris_Bryant]

Unless the vehicle has a charging solenoid, that’s normal- for an always on tv charge line. You just put another battery in the circuit.