Help hooking up power to back up camera

fijidad wrote:

dougrainer wrote:
1. The original Back up camera system has NO Reverse wire connection at the REAR of the motorhome. The reverse is activated at the front Dash area to the original dash monitor and when the reverse transmission Hyd switch is engaged the wire is sent to the Dash Monitor harness and the Dash Monitor then sends the activation/power thru the multiwire harness connected to the rear camera.
2. The 3 wires you mention. Are these at the rear Tailight/Reverse light lamp assbly? If so, then the Yellow is usually the Reverse Pos wire. The Green would be running lights and the white ground.
3. The SAFE way to test is what I do. I have someone at the drivers seat with the Air brake engaged and then run the engine and have them shift to reverse WITH THEIR FOOT ON THE BRAKE PEDAL. Doug

The three wires feed the back up light bulb, and I was trying to determine which is power and which is ground in order to hook up the two wires from the Garmin wireless transmitter.

It would help to see the wiring diagram, but I've not found one in the stuff I have, nor on line.

The white will be ground on Monaco products. Usually the Reverse BULB is a single pin bulb. But, since you state 3 wires, are you positive that the other wire is NOT the running lights? Have you removed the bulb to see if it has 1 contac or 2 contacs on the bottom of the bulb? Is the rear assbly have both the Running and Reverse light bulbs in one assbly? Turn on the running lights and see which wire is 12 volt positive. Is it possible the assbly has the BRAKE light bulb and the Reverse light bulb? Doug