Troubleshooting Humming Brakes when Hazard Lights Flashing On 1996 Chevy C1500

Question:

I have a 1996 chevy C1500 that I pull our enclosed trailer with all lights work fine as do the breaks but when I use the 4 way flashers the breaks hum with the flashers when testing plug on truck with 4 ways on the to plugs for them flash bright and the one for the breaks is dim has been like that from the time I wired it both plugs are spotless

asked by: Robert W

Helpful Expert Reply:

A pulse preventer, part # 5501, should stop this problem. The flashers are sending feedback into the brake controller and pulsing it.

Find the spot where the brake controller is spliced into the wire from the cold side of the stoplight switch. This is typically the red wire on the brake controller.

Then just past this (away from brake controller) cut the vehicle stoplight wire and install the Pulse Preventer inline with the yellow wire on the side that the stoplight switch and brake controller are on and the brown wire on the side going to the vehicle's brake lights. This connection will stop the hazard signal from feeding back to the brake controller.

expert reply by: Chris O