Troubleshooting Low Voltage Output On Blue Wire From Brake Controller On 2002 Ford F-150

Question:

the blue wire voltage low what can be the problem

asked by: Morgan

Expert Reply:

A great way to test the brake controller blue wire output is to use a Circuit Tester, like part # PTW2992. You will want to test the blue wire at the back of the brake controller. If that is low, then there may be an issue with the vehicle wiring. The bulb in the tester will place a load on the wiring, and you can tell if you are getting full voltage by the brightness of the bulb in the tester.

If you find that the bulb is dim with the brake controller set at maximum setting, you will want to check the brake controller ground, power and brake switch wires to make sure they are properly connected.

You can also check the vehicle trailer connector for any signs of corrosion that could be causing the voltage drop. If you find any signs of corrosion, you can clean the connector and then apply some dielectric grease like part # 11755 to the connections. This will help keep dirt and moisture out of the electrical connection and help prevent corrosion in the future.

If everything checks out, you may have a faulty brake controller and will need to replace it.

If you find you need to replace it, I recommend the Tekonsha Prodigy P2, part # 90885. This is a proportional brake controller that will activate the trailer brakes in proportion to your vehicle's braking action. This controller also helps reduce the brake wear on your towing vehicle.

I also recommend the Tekonsha Plug-In Wiring Adapter, part # 3035-P. I have attached a link to an installation video for the P2 brake controller and adapter you can check out.

I have also attached links to some helpful articles for brake controllers you may want to take a look at.