Troubleshooting Trailer Lights Dimming When Pushing Brake Lights Activated on Commercial 7-Way

Question:

Putting new wire and taillights in a semi trailer Left and right blinker work properly but when a blinker is on and you step on the break, The blinker goes a little dimmer And the brake lights Flash opposite of the blinker light

asked by: Kent R

Expert Reply:

It sounds like you are having a ground wire issue. That would explain why the lights are dimming and you are getting the flashing. You will want to check the ground terminals where they connect to the trailer and you may need to use a larger gauge ground wire going from the trailer to the Pollak HD, 7-Pole Round Pin Connector # PK11702. Also be sure to check the wiring on the Pollak Heavy-Duty, 7-Pole, Round Pin Trailer Wiring Socket # PK11720 to ensure it has a good ground connection.

expert reply by: Bud M