Troubleshooting Tekonsha Primus IQ Brake Controller Not Detecting Trailer on 2015 GMC Sierra

Question:

I recently installed a Primus trailer brake controller on my truck. It shows up as not connected even when the trailer is connected. 100 positive the trailer is wired correctly with trailer brakes. What’s weird was, I recently went to the store without the trailer, as I was leaving I started my truck and it showed the trailer brakes were connected and even went to 4.0 power when I pressed on my brakes to put the truck in reverse

asked by: Justin

Expert Reply:

If your Tekonsha Primus IQ Brake Controller # TK90160 isn't detecting a connection with the trailer (and sometimes is when there isn't a trailer....) then the first thing I recommend looking at is the 7-Way connector on both the truck and trailer. Just visually inspect both connectors and look for any debris or corrosion inside/around the pins that may need to be cleaned out.

A lot of times some rust or debris can prevent a good connection between the trailer and cause issues when a trailer isn't even hooked up.

If both connectors look good you will want to focus on your truck since you are pretty certain the issue isn't on the trailer. The brake output wire (blue) from the controller to the 7-Way is what carries the circuit that would detect a trailer connection. With this in mind you will want to try and trace this wire as far as you can, looking for any pinched or damaged portions that need to be replaced.

Assuming this particular wire was already installed at the factory it may be difficult to gain complete access to it. If this is the case then it might be a good idea to simply bring the truck up to a local dealer to have them take a look.

expert reply by: Chris R