Proper Wiring of a Hitch-Cover Brake Light so it Does Not Blink when Turn Signal is Activated

Updated 11/04/2009 | Published 11/03/2009

Question:

Hello, As an additional safety, I want to install an after-market hitch-cover brake light that will automatically illuminate bright red whenever the vehicles brake pedal is depressed. Obviously, no trailer is attached to my vehicle at this point! The wiring instructions that came with the new hitch-cover brake light made by Bully says to simply connect their white wire to chassis ground and to connect their green wire to the existing green wire right turn signal/brake light that comes out of the common flat 4-wire connector used for vehicle/trailer wiring. My vehicle has a standard 3-wire dual-filament bulb that allows the green wire to activate the right turn signal AND the stop light simultaneously. Therefore, when I hook up the new hitch-cover brake light hot wire to the existing green right turn/brake wire, the new hitch-cover brake light will blink whenever the vehicles right turn signal is activated yes... it also does come on steady when the vehicles brake pedal is depressed. How can I isolate this wiring so that my newly installed hitch-cover brake light ONLY comes on when the vehicles brake pedal is depressed and NOT when the right turn signal is activated? Is there any type of after-market wiring converter or blocking diodes that could be installed between the right turn/brake light green wire and the left turn/brake light yellow wire that would allow my newly installed hitch-cover brake light to ONLY come on when the vehicles brake pedal is depressed and NOT when the turn signals are activated? Please HELP me... this wiring quirk is driving me crazy! Thank you very much for your help! Sincerely, Tom J. Hinkley

asked by: Tom J

Expert Reply:

If you want your hitch cover brake light to only work with the brake lights, I would recommend that you use a 2 Wire Loop, item # 9651P, to make a separate connector for your brake light hitch cover. Then run the white wire to ground and splice the red wire to the third brake light circuit which does not blink when the brakes are applied and the turn signals are activated. You will have a separate two wire connector for the hitch cover with this setup.

At this time I do not know of any converter or diodes designed to block the turn signal from the trailer wiring to allow the hitch cover to remain on constant when the turn signal is applied.

We do have hitch covers that do not blink with the turn signals and use the standard 4-Pole trailer connector, (see link).

expert reply by: Robert G