Is it Normal to Only See 9 Volts on the Output Circuit of a Brake Controller

Updated 04/13/2016 | Published 04/11/2016

Question:

I am getting 9 volts at the trailer pin connector when the trailer brakes are applied is this the correct voltage Regards

asked by: John F

Expert Reply:

Brake controllers allow you to vary the voltage applied to the trailer brakes to allow for different braking power. If the controller is set to it's max output voltage it should be right at 12 volts. Be sure to have the vehicle running too so that you don't see any voltage drop off just from the alternator.

If the controller has it's gain turned all the way up and it's only at 9 volts then that would indicate you have an internal problem and the controller would need to be replaced.

I attached a troubleshooting article on brake controllers for you to check out as well.

expert reply by: Jameson C