Is 3.5 Volts Too Low to Lock Up Trailer Brakes

Question:

i recently built a trailer and installed electric breaks. they are getting power but it is really weak. i checked the voltage coming out of the 7 wire plug on the bumper of my truck and im only getting 3.5 to 4 volts . so i guess my question is , is the low voltage coming out of my truck the problem and if so what is the output supposed to be ?

asked by: Cameron C

Expert Reply:

The max voltage a brake controller can put out is 12 volts. That's typically enough to lock up the trailer brakes as long as they are properly adjusted. Since you said you are only getting 3.5 to 4 volts then that's why you have weak brakes.

You need to increase the gain or output setting of your controller till it reads a higher voltage. With a higher voltage the brakes will apply harder.

expert reply by: Jameson C