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Ford F-150 Camper/Shell 3rd Brake Light Wiring

This tech article was originally posted at It is primarily intended for Ford trucks but most likely also applies to other Ford models.

Tools Needed:

Parts Needed:

Parts Cost:

$5.00 , if you need to purchase a 3rd brake light it could be $20-50 depending on how fancy you want to go.


Nearly all Ford F-150 trucks made in 1997 and later have a 2 light taillight system. This can't be easily wired into a 3rd brake light because you need a logic circuit to somehow only turn on the 3rd brake light on your camper shell when the brakes are applied and not flash with either signal light.

Fortunately Ford has included a light green wire in the rear bumper wiring harness exactly for this purpose. It isn't connected to anything. It comes from the switch on the brake pedal before it goes to the "multi-function" switch that makes the logic for the tail/turn lights. It is actually meant for mounting a 3rd brake light on a camper/canopy or if you have a large travel trailer with a 3rd centre-mounted brake light.

Make sure you use your safety glasses while under the vehicle to avoid dirt dropping into your eyes.


Follow my instructions completely at your own risk. I take no responsibility for any accuracy in my instructions.

Photo of wiring harness at rear of the truck

Photo of the main wiring harness (look for the light green wire)

Photo of soldering preparation
Photo of cutting the wire
Photo of the connector
Photo of heat shrink procedure

Photo: Insert the connector through the hole in the box... Photo of wiring behind taillight  Photo of taillight removed, fishing wires through the hole

Photo of plastic zip-tie on the wires to prevent them from falling through the hole

Photo of ground wire and connection

Photo of finished wiring job

The final product! Success!

On my canopy there is also an electrical connector on the passenger side rear corner just like the 3rd brake light connector. I'm saving the other half of that quick release connector to eventually run a power wire for the dome light inside the canopy.

Editors note: I know what some of you are thinking, there are already 3 brake lights in the F-150. Well, that's true, technically this is a fourth brake light ;-)

This article has been generously donated by Peter Ferlow.