Electric Over hydraulic Trailer Brakes Not Working on a 2006 Eagle Trailer with a P3 Controller  

Question:

Expert Reply:

Regarding the ground, if the fire wall is painted, that could be causing a bad ground issue. Just make sure it is on a bare metal surface. You can also check to make sure both the vehicle side and trailer side connectors are clean and free of corrosion and that the connectors are properly grounded.

Next, I would unplug the brake controller and test the vehicle wiring using a circuit tester like # PTW2993 or a multimeter like # PT89ZR. Test the wiring for voltage when you step on the brake to make sure a signal is coming through. If it is, plug the brake controller back in for further testing. If there is no signal, something is wrong with the vehicle wiring. You may have a fuse or relay that is blown or needs to be added to allow the brake controller to function. Check your owner's manual and/or the power distribution box for a diagram of fuse and relay locations and functions.

With the brake controller connected, probe the blue wire when you step on the brake and/or use the manual override. If it shows a correct signal equal to what it is set at, you will need to test the 7-Way connector next. If there is no signal, then something is wrong with the internal circuitry of the brake controller or the wiring harness and it or they will need to be replaced.

At the 7-Way, test the pin for electric brakes (should be the pin in the 5 o'clock position) while someone in the 4Runner steps on the brakes and then uses the manual override. If the signal is getting through like it should then the problem is with the trailer wiring. You will need to make sure the hydraulic pump has constant 12-volt power ran to it in order for the brake controller to fully activate it. You can test it by using a separate 12-volt power source to power the hydraulic pump and then engage the brake or manual override to see if that solves the problem.

If the signal is not getting through to the 7-Way, there is a problem with the wiring somewhere between the connector and the brake controller that you will need to run down.

Last, you may need to set up the brake controller as if it was the first time. You will follow the Adjusting the Power to the Trailer Brakes portion of the instructions, linked below for reference, on page 5. Once completed, go ahead and adjust the boost setting as needed.

expert reply by: Michael H

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