Troubleshooting Low Voltage on Tekonsha Primus Brake Controller

Updated 03/04/2015 | Published 03/03/2015

Products Featured in This Question

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

(2158)

$90.04

Tekonsha Prodigy P2 Trailer Brake Controller - 1 to 4 Axles - Proportional

(2763)

$159.19

Question:

on my recent trip with the caravan I noticed I could (not) increase or decrease my voltage setting beyond .3 to .5? Yet if I use the overide slide it pulls my caravan up fine?? Please help.

asked by: Joe

Expert Reply:

The Primus is a proportional controller so you actually have to be moving to get the proper voltage sent back when using the brake pedal, but the manual override will send the full power (up to what it is set to) back to the trailer connector.

With that said, it sounds like you are losing voltage somewhere between the brake controller and the trailer connector. First thing I would try is sliding the manual override a few times and adjusting the gain knob up and down to help clear the contact points.

Also make sure your controller is properly installed and leveled according to the instructions.

Use your tester on the blue brake output wire at the rear of the brake controller, and verify that you are getting 12-volts exiting the controller with the gain turned up to maximum and the manual brake switch applied. If you are getting significantly less than 12-volts at the rear of the controller, test the black wire feeding power into the controller. If you have 12-volts going in on the black wire, but less than that going out on the blue wire, the controller is bad and needs replacing.

I attached a few help articles on troubleshooting brake controllers for you to check out as well.

For a brake controller replacement I would recommend the Prodigy P2 Brake Controller part # 90885. This is our best selling brake controller because of how well it works and how easy it is to setup.