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Weak Trailer Brakes On Trailer Towed by Ram 3500 or Chevy 2500


What is the correct voltage needed to apply brakes I have a new ram 3500 and my dad has a Chevy 2500 and both of them with a meter is only showing 4 to 5 volt for the brake is this right? Im having trouble not getting enough brakes on the trailer, any thing you can suggest is helpful,


Expert Reply:

Which brake controller are you using? What are the years of the trucks? If using factory integrated brake controllers you may need to adjust the gain (same on aftermarket controllers) to increase the output voltage. Trailer brakes work on varying voltages. At 4 to 5 volts that is not quite half of full power. At 12 volts the magnets would be fully energized.

Also, where are you testing for voltage? Adjust the power output on the brake controller to the maximum and then have someone fully apply the manual override while you test the pin in the 5 o'clock position on the 7-Way. If it is not showing 12 volts then you will need to test the controller.

To test, you will have to sever the brake output wire (usually blue) a few inches from the back of the controller. Then you would apply the manual override on full and test the end of the blue wire coming out of the controller. If it shows 12 volts then there is a wiring issue in the wiring between the controller and the 7-Way you will need to track down. If it does not show 12 volts then there is something wrong with the brake controller and it will have to be replaced.

Testing with the brake pedal does not always work because on many brake controllers the vehicle has to be moving for the controller to send back the amount of power it is set for.

Nine times out of ten weak trailer brakes indicate that the brakes need to be adjusted. Basically you want a slight but constant drag of the pads on the drum when the wheel is turned.

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