Troubleshooting RV Battery Dying On Long Trips

Question:

My 2011 Audi Q7 has a factory hitch and wiring. However, there appears to be no hot lead for trailer brakes. My RV battery goes dead on long drives with frequent braking. Can I run a hot lead from the Audi battery terminal without confusing the complicated Audi charging system?

asked by: Rustin C

Expert Reply:

I would first verify that the 7-way connector on your 2011 Audi Q7 has constant 12v power to the 1 o'clock pin which is the auxiliary power pin. To do this you will need a circuit tester like # PTW2993. If you do not have 12v power I recommend checking your vehicle's owner's manual to find the fuse location and check for a blown fuse, or the factory may not have hooked up the 12v auxiliary power to the battery.

If you need to add the 12v power, you will need to run # 10-1-1 wire which is sold by the foot with a circuit breaker # 9510 from your vehicle's battery to your 7-way connector.

If you have 12v power to that pin you will need to test the wire going to your trailer battery from the 7-way connector. If you do not have power at the battery end you will need to trace the wire to the connector and check for damage or bare wiring showing and replace it.

The trailer brake wire goes directly from your vehicle to the trailer brakes, and doesn't pull any power from your trailer's battery.

I included an article about trailer wiring for you to take a look at.