Troubleshooting P2 Brake Controller in 2010 Ford F-150 Shows Connected but No Function

Question:

I have a 2010 Ford F150 Crew Cab with factory tow package. I installed a P2 brake controller and installed the fuses that came with the truck. When my travel trailer is hooked up the night time lights work and the display shows a Cinch but brake lights dont work, and the trailer brakes will not engag. I have read many installation posts and found some that say they had to take their truck to the dealer to have the trailer brake activated when installing the OEM controller. I called 2 Ford dealers in my area, both told me activation shouldnt be necessary. Do you have any ideas why the controller is not working?

asked by: Nathan

Expert Reply:

If your truck did not have a factory brake controller in it then the # 22292 and the P2 # 90885 should install just fine without a trip to the Ford dealer. If you did have an integrated controller that you are replacing then yes you would need to make a trip there.

The fact that the controller is displacing .C indicates that the controller is detecting a trailer and is connected fine. What happens when you slide the manual override lever of the controller with a trailer connected? Does it show voltage there? You can test the controller setup to pin point the problem.

Testing the brake controller is fairly easy. Sever the blue brake output wire near the brake controller leaving enough room to reconnect it and then apply the manual slide. Using a circuit tester like part # PTW2993, you should get output to the controller side of the wire you severed. If the manual slide activates the trailer brake output wire properly, try the brake pedal. If the brake pedal activates the brake output properly also then the problem is farther back either in the vehicle wiring or on the trailer.

If either the brake pedal or the manual slide are not functioning properly you will need to test the wires going into the brake controller. Make sure you have power entering the brake controller on the black wire. On the red wire you will only want power when the brake pedal is pressed.

If there is power on the red wire before the brake pedal is pressed you have connected the red wire from the brake controller to the wrong circuit. You would then need to find the brake switch wire that has power ONLY when the brake pedal is activated.

If these connections check out and the brake controller is properly grounded then there is possibly a problem inside the brake controller.

I am including a link to a video that will show you how to test the wiring on a brake controller.