Will Proportional Trailer Brake Controller Generate Brake Signal From Pressing Pedal When Still

Question:

I have recently installed a brake controller for my rv. Maunual override works fine but it does not work when I press the brake

asked by: Ricky B

Expert Reply:

If the brake controller you installed is the often-preferred proportional type, such as the Prodigy P2 # 90885 or P3 # 90195, then it is normal for the unit to not generate an output signal if you press the brake while the vehicle is stationary.

Proportional trailer brake controllers use an internal sensor, an accelerometer, to detect motion. That motion is what triggers the controller's output, by detecting the tow vehicle's rate of deceleration. This lets the controller send out a braking signal to the trailer that is proportional to the tow vehicle's rate of deceleration. If the vehicle is sitting still, the controller will not sense motion and so will not generate any output signal.

The other potential cause for the controller not reacting to you pressing the brake pedal is a bad connection for the red wire on the controller - which connects to the RV brake light circuit. This red wire takes in the signal from the tow vehicle brake light circuit and this signal serves as the controller's input. If the red wire is loose then no signal will reach the controller when you press the pedal.

Two helpful articles concerning trailer brake controller installation are linked for your reference.

expert reply by: Adam R