I am not familiar with the modern car circuit design and was hoping some advice on finding the positive/ground wires. I could not find the wiring diagram for my car online.
I have a 2015 Mazda 5 and I am installing a rear view camera which requires power from the backup light. Each light bulb has two wires, positive and ground. Shod I do continuity test with a resistance meter by using one of the wires goes to the bulb and another test probe on a good ground from the chassis? or should I measure the 12v by putting the car in reverse with the same connection and see if there is voltage ( yes: positive; no: ground)?
I ask because the continuity test seems simpler and does not require power. But I noticed some modern cars has light control module or relay so maybe the ground wire is not grounded when not energized?
I have a 2015 Mazda 5 and I am installing a rear view camera which requires power from the backup light. Each light bulb has two wires, positive and ground. Shod I do continuity test with a resistance meter by using one of the wires goes to the bulb and another test probe on a good ground from the chassis? or should I measure the 12v by putting the car in reverse with the same connection and see if there is voltage ( yes: positive; no: ground)?
I ask because the continuity test seems simpler and does not require power. But I noticed some modern cars has light control module or relay so maybe the ground wire is not grounded when not energized?