Troubleshooting Backup/Observation Camera Wiring Where Reverse Light Is Constant With Running Lights

Updated 04/19/2019 | Published 04/18/2019

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Question:

Connected an auto-vox to backup wire black for full time viewing behind the rv while driving. Connected the ground to white wire. Choices are green white and black. Camera comes on fine with driving lights on but the reverse light is on with the driving light on the rv taillight. Turn signal works fine as well as brake light.

asked by: Jeff K

Helpful Expert Reply:

Thanks for the photo and explanation. It sounds like you have connected your camera to the running light circuit which will give you constant power, but it appear one of your other wires is not for your ground connection. Normally white is a ground wire, but on a 3 wire system like you state with reverse light function, one of those wires is dedicated only to reverse power. Your three wires will have the following functions:
One is running/park lights
One is reverse lights
One is combined stop and turn light

You will want to use a circuit tester like # PTW2993 to determine which wire is which function. Often trailer lights will ground through the mounting hardware, so you should wire your camera so that it is connected to the running/park light circuit and then to ground.

expert reply by: Jason S