Troubleshooting Low Brake Output Brake Voltage on a 2007 NU WA HitchHiker 34 5th Wheel

Question:

I have a 2007 NU WA Hitchhiker 34ft 5th wheel with electric brakes. The truck brake controller is putting out 12 volts where the trailer cord plugs in. However, I get very little braking at the trailer when I apply the controller and I have it set at 10. At 5, the braking is not even noticeable. However, the brakes do lock up when using the emergency cord. The four trailer brake assemblies were just completely replaced last week and the mechanic said that he was getting about 3 volts at each brake. He used his 2006 Ford 250 but he got about the same amount of braking with his controller. I talked with the Ford dealer and he had no suggestions. Any thoughts about what I can do next? Thanks

asked by: Larry

Expert Reply:

It sounds like there is something wrong on the brake output circuit of your trailer. The reason I say that is because you have 12 volts at the connector on your 2008 Ford F350 brake controller but somehow only 3 volts are making it to the brake assemblies.

Since the brake assemblies are brand new that eliminates them from being the problem. What I would do is start at the back of the connector with a voltmeter like 7-Function Digital Multimeter # PT89ZR and test the circuit for 12 volts there. Basically you want to keep working your way back on the circuit with the manual override of the controller slid trying to find where the voltage drop is and fix as necessary.

Also, you want to make sure you are using 10 gauge wire like # 10-1-1 for this circuit and that the assemblies are grounding to a clean metal surface.

I attached an FAQ on trailer wiring for you to check out also.

expert reply by: Jameson C