Installing Third Brake Light and Dome Light into Truck Bed Cap


Best way to hook up the brake and interier lights on truck cap. Truck 2001 Silverado 3/4 HD reg. bed w/ trailering package. 7 way connector,light blue wire out of wire harness by plug is caped off ? Thank You

Expert Reply:

If you will take a look at the wiring harness up above the spare tire, you should find the connector that the 7-way plugs into. If you trace the loom back just a bit, you will find a light blue wire that is used for the 3rd brake light for your truck cap. If you will follow the provided link, see Step 3 figure B. This photo will show you the location of this wiring harness above the spare tire.

For the interior dome light, there are two common methods both of which will require a switch, such as part # PK34513. You can either tap the feed for that dome light into the tail light circuit, which means that the light will only work when the running lights or headlights of the vehicle are switched on, or it can be tapped into the 12-volt feed that runs to the 7-way. I would recommend using that 12-volt feed, so that you will not need to turn on the head lights to activate the circuit.

expert reply by:
Michael L

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