Can You Get Third Brake Light and 12 Volt Power For Camper Shell From 7-Way Trailer Connector

Updated 12/06/2012 | Published 11/29/2012

Products Featured in This Question

Pollak Replacement 7-Pole, RV-Style Trailer Connector Socket - Vehicle End

(732)

$16.16

Firestone Fuse Circuit Tap Kit

(39)

$20.98

Cordless Circuit Tester

(15)

$19.26

Question:

Can I find a wire to connect to at the 7 pin trailer connector to wire a third brake light in the pickups topper/shell? What color wire am I looking for that will work for this purpose? I also need a 12 volt source for the utility light in the topper for light inside the bed of the truck. This is mounted just above the rear window. It has a switch on it like a dome light. Are these possible from the wiring harness that goes to the 7 pin connector?

asked by: Pete W

Expert Reply:

On a 7-Way trailer connector, the brake lights and turn signals are combined on the same circuit so you cannot tap into the wiring there for a third brake light. If you did, the third brake light would blink with the turn signal.

Normally if you follow the wiring harness back (towards the front of the vehicle) you may find additional wires that you can test with a circuit tester like # PTW2979 if needed to see if there is a third brake light wire there.

You can also use the stop light circuit or CHMSL (center high mount stop light) circuit fuses and tap in there using a fuse tap like # F2526 as an example. To find these fuse locations under the hood, use the owners manual or legend on the power distribution box lid.

Another thing you can do is contact a local truck bed topper dealer and they may know where a third brake light wire is located that will be easy to access.

The 12 volt circuit on a 7-Way can be used for the light. Since it is already on a switch you can connect the switch power wire to the 12 volt circuit (wire in the 11:00 position if looking at the back of the 7-Way). Otherwise, since it is on a switch the light could be connected directly to the battery.

expert reply by: Michael H