Troubleshooting Tekonsha Primus IQ Brake Controller Sending Minimal Power with Brake Pedal Depressed

Updated 03/26/2019 | Published 03/25/2019

Question:

I was doing the spring grease and brake check on my TT, While hand spinning the wheels with an obvious scrapping sound of the brake shoes, the brake pedal wouldnt stop the wheels. When I put a true 12v on the TT pigtail the wheels stopped. then I found that the controller was only putting out 5v with the brake pedal and 14v with the manual override. the 5v was at both the backside of the controller and the rear connector on my suv. do I need to replace the controller? it is proportional type, does it get to 12v while rolling? the controller is 9 years old.

asked by: Curtis C

Expert Reply:

I have good news.

As you mentioned in your question, the Tekonsha Primus IQ Brake Controller # TK90160 is a proportional unit. This means that the controller is going to send a brake output back to the 7-Way in proportion to the vehicle's deceleration. Because of this it will send minimal power when testing it by depressing the brake pedal when the vehicle is parked. The manual override will always send back full power which is why you got 14V when applying it.

This essentially means that your controller seems to be working exactly as it should. If you are still concerned you can also take your trailer out for a quick test drive to make sure the brake pedal powers the brakes properly.

expert reply by: Chris R