Trailer Brakes Pulsing With Hazzard Signals On 1993 Ford F-250
Question:
i wired a trailer and brake on a 93 250 everything is wired acording to diagrams with all new wires on the trailer. but when i turn on the 4way hazzard light the brake controler lights up and stay on and the brake pulse even with it set at the least agresive braking setting. so i ordered a pulse preventer and it still does the same thing. i also noticed that when the ignition is turned off it works as it should but when the key is on the brakes come on with the 4 ways. any ideas. also i was wondering if you would take back the pulse preventer since it did not fix the problem. thanks
asked by: Chris
Expert Reply:
Lets make sure the Pulse preventer is installed properly. When you install the pulse preventer you will be installing inline on the vehicle brake output (cold side) wire, after the connection where the brake controller is spliced in.
Find the spot where the brake controller is spliced into the wire from the cold side of the stoplight switch. 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 vehicles brake lights. This connection will stop the hazard signal from feeding back to the brake controller, eliminating the pulse problem.
Another thing you may want to check is that you have the brake controller hot wire (black wire) connected to the vehicle battery through a 30 amp circuit breaker, item # 38630. If the black wire is spliced into a circuit that goes through the ignition then this is most likely the problem.
If none of these fixes work the only thing I can think to do is go back to the red wire with a voltage meter and check that it has no voltage except when the brake pedal is pressed. Do this both with the vehicle running and with the ignition off, hazards on and hazards off. If there is any voltage present without the brake pedal pressed you either have the brake controller attached to the wrong wire or there is a problem in the wiring on the truck.
