Wiring a Bed Cap with a Third Brake Light and a Dome Light

Updated 09/01/2026 | Published 08/25/2026

Products Featured in This Question

Curt T-Connector Vehicle Wiring Harness for Factory Tow Package - 7-Way and 4-Pole Flat Connectors

(775)

$36.46

Curt T-Connector Vehicle Wiring Harness for Factory Tow Package - 4-Pole Flat Trailer Connector

(770)

$38.26

3rd Brake Light Logic Module

(202)

$21.03

Question:

I have a 2019 toyota tundra, and need to wire the brake light on my fiberglass cap, do you have a no-splice kit that will give me brake/dome light for the cap? Thank you!

asked by: Gary H

Expert Reply:

Thanks for letting us help Gary. Unfortunately, we don't have a completely plug-and-play, no-splice kit that will provide both the third brake light and dome light functions for your truck cap. However, since your Toyota has the factory 7-way, you can use that as the starting point and keep the installation fairly straightforward.

The Curt T-Connector Vehicle Wiring Harness # C55384 can be installed inline with your existing factory trailer connector, and you'll still retain full use of the factory 7-way. For the third brake light on the cap, connect the yellow left stop/turn wire and green right stop/turn wire from the # C55384 to the two yellow input wires on the Pacer 3rd Brake Light Logic Module # PP20-702. The output wire from the module then connects to the cap's third brake light. The logic module is necessary because the 4-way wiring combines the brake and turn signals on the same circuits. The module separates those signals to provide the brake-only signal needed for the center brake light, so it won't flash with either turn signal.

For the cap's dome light, the # C55384 won't provide the constant 12V power you need. You'll need to access the 12V auxiliary power circuit from the factory 7-way separately and run that power to the cap's dome-light switch.

What are you going to be storing under the cap?