Troubleshooting Lack of Brake Lights on Trailer with Newly Installed 7-Way on Service Truck

Question:

I installed a 7 blade receptacle on my service truck to pull a trailer, the trailer is equipped with electric brakes but the truck doesnt have a brake booster, I have running lights and turn signals but no brake lights, I wired the blue brake booster wire to the brake light wire on the truck and have brake light power to the receptacle but still no brake lights, do I need to bypass the electric brakes on the trailer to engage brake lights or just install a brake booster? Thanks.

asked by: Gregg F

Expert Reply:

On your service truck, the 5 o'clock pin is for a brake controller output. There is not a light on this location, but just power to go to the trailer brake magnets. The trailer brake lights will run with the turn signal lights on each side. So you will have left turn and brake and right turn and brake. I've attached an article to assist.

It sounds like you have a separate brake light on your service vehicle, so you will use the wiring converter like # C59236 to convert your 3 wire system to a 2 wire system compatible with your trailer combining those functions.

Then I recommend using the brake controller wiring kit # ETBC7 to upgrade to the 7-way and also add the wiring for a brake controller. For your controller, I recommend the Prodigy P3 # 90195 which is a favorite with our customers based on ease of use and reliability. The LED screen is a big help with diagnostics as well as day to day function. I've attached a video to assist.

expert reply by: Jason S