Should Red Wire of Brake Controller Have Voltage When Vehicle Brakes are Applied

Question:

Simple question- if I connect a voltmeter to red wire that goes into brake controller with a ground also should voltage appear when I press brake pedal? Vehicle running of course/ My manual control works, but brake pedal does not work controller. That suggest either a faulty controller, or a disconnect of wiring. Thank you so much for yor assist.

asked by: John R

Expert Reply:

Hey John, yes if you used a circuit tester like the part # PTW2993 to probe the red wire of the brake controller you should see voltage when the brakes are applied and none when released. Based on your controller working with the manual override it's probably this circuit that is the problem. Make sure it's connected to vehicle wiring properly and also that there aren't any blown third brake light fuses on the vehicle.

If the voltage is there the controller is bad so it would be time for a new one which the P2 part # 90885 would be a great option that is very reliable.

expert reply by: Jameson C