Trailer Brakes Apply when Emergency Flashers/Hazard Lights are On in an Older Ford Truck

Updated 06/12/2018 | Published 06/11/2018

Question:

Using the P3 on an older Ford Truck and when the Flashers are on the brakes apply. Is there a way to be able to use the flashers and not have to disable the brake unit

asked by: Frank

Expert Reply:

Yes, you need what is called a pulse preventer, # 5501.

You mentioned that you have an older Ford truck. Depending on how old it is you may need to connect the brake controller red wire to a different location on the truck. If your truck is a 1989 to 1991 model year you will need to locate the crescent-shaped turn signal harness located on the steering column under the dash. The connector will have two rows of wires (a row of 4 and a row of 7). Attach the brake controller red wire to the light green wire which is the second one in the row of seven.

expert reply by: Michael H