Primus Brake Controller Does Not Show Output with Brake Pedal

Updated 07/28/2015 | Published 07/27/2015

Products Featured in This Question

Tekonsha Primus IQ Trailer Brake Controller - Up to 3 Axles - Proportional

(2171)

$105.07

Hook Probe Circuit Tester

(65)

$13.35

Question:

When you press the manual braking button a number comes up to show you how much brake is being applied to the trailer brakes. If you are depressing the brake pedal, which should be applying brakes to the tow vehicle and the trailer, and the display doesnt show a number like when you press the manual button but just displays .c, is there a problem with the brake control unit? Are the brakes to the trailer not being applied? In other words, if Im hitting the brakes which should be the tow vehicle and trailer brakes together, should the display change to a number rather than continue to just read .c or .c. if I have boost enabled?

asked by: Levi

Expert Reply:

You should be seeing an output number when you are using the brake pedal just like you would when using the manual override on the Primus brake controller # TK90160. If it is not that indicates a problem on the red wire which is input from the brake switch.

You can use a circuit tester such as # PTW2993 to test the red wire. It should show power when you step on the brake pedal. If it does not, then it is either connected to the wrong brake switch wire or you could have a blown stop light or CHMSL fuse.

expert reply by: Michael H