Primus Brake Controller Suddenly Jumps to 3.1 Power Level

Question:

Im having an issue with my Primus IQ. At times more than 50 of time when engaging the brake and I have my boost set to 0 showing .c on controller, the brake controller engages the boost I get automatic 3.1 showing on initial braking. This causes my trailer brakes to either lock up, or to severely slow my tv down cause the back end to dip due to tv brakes not being engaged as strongly when braking usually under 25 mph, or going uphill. This is rather annoying, as I cant predict when this will happen. Do I have a faulty brake controller, or am I missing something?

asked by: Sean S

Expert Reply:

Is the boost actually coming on or is it erratically going to 3.1 and still showing the single dot indicating the boost is off? If the boost is actually coming on then it would be a faulty brake controller. If it isn't coming on then the issue could be that the controller is mounted outside of the range specified in the instructions.

The Primus # TK90160 can be positioned level and up to 90 degrees nose up. It cannot be tilted or turned to the side at all. If it is outside of that range then the controller can behave strangely especially on hills.

If that isn't the issue then it could be a short and mostly likely it will be a short in the vehicle or trailer side connector caused by corrosion either on the pins or where the wires attach. Check those to see if that is the issue.

I have also included a couple of links on testing and troubleshooting brake controllers for you.

expert reply by: Michael H