What Circuit Should be Used for Wiring Up Third Brake Light on a Camper

Question:

The subject truck has been wired for a 3rd brake light on an ARE cap. I used the white with purple striped wired near the spare tire as I found on this forum but it is always outputting 3 volts which makes the brake light illuminate very slightly all the time. Is this normal I doubt it? If not how can it be corrected? Thanks

asked by: Dutch

Expert Reply:

For the lighting of a third brake light you would not want to use a circuit that has 3 volts of voltage at all times. You need to find a circuit that sees 12 volts only when the brakes are applied. You can usually find this circuit at the brake pedal switch. Or at the fuse box of your truck for the CHMSL (center high mount signal light) circuit.

Or you could use the converter part # 118158 to convert your taillight signal to having a dedicated brake signal.

expert reply by: Jameson C