Brake Lights Blink on a New Trailer Pulled by a Ford F-550 with the Hopkins Engager Breakaway Kit  

Question:

Expert Reply:

This is certainly an odd situation. The auxiliary power wire coming from the truck should have constant power, not pulsating power and the brake light wires are on separate circuits from the auxiliary power wire and the electric brake output wire coming from the truck and the breakaway kit.

The first step I would take is to test the trailer connector on the F-550 using a circuit tester like part # PTW2993 to make sure the vehicle side connector is functioning properly. The pins for the brake lights will be in the 3 and 9 o'clock position (see photo). Also, I am not sure which pin from your trailer connector is powering your breakaway battery, so I recommend testing the pin in the 1 o'clock position and the center pin (see photo). The pin in the 1 o'clock position is for 12-volt power from the vehicle battery and the center pin can be used for reverse lights or as an auxiliary 12 power source.

If the center pin is wired for auxiliary 12-volt power, then both pins should show constant power, not pulsating power. If either of the pins have pulsating power, then there is a problem with the vehicle trailer wiring. Also, the 3 and 9 o'clock pins should show constant power when the brake pedal is pressed and pulsating power when the turn signals or hazard lights are on.

If the vehicle side trailer connector is functioning correctly, then we will want to take a look at the wiring on the trailer. The first step I would take is to take apart the trailer side connector. Make sure the wires are secured in each of the terminals and not touching another wire. If wires are touching each other, that could mean power is jumping from one circuit to another causing the brake lights to flash. I also recommend checking all of the ground connections for the trailer connector and trailer lights.

The next step would be to check the wiring for the breakaway kit. I have attached a diagram showing how the breakaway kit should be installed. You will notice, the wires for the brake lights are separate from the breakaway kit, so it should not cause the brake lights to blink. Keep in mind, trailer manufacturers do not use an industry standard color code for their wires, so your brake light, 12-volt power and electric brake wires may be different colors than those indicated on the diagram.

If you cannot find the problem or a solution after following these steps, let me know what you come up with and we can take further steps.

expert reply by: John H

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