Should P3 Brake Controller Show No Trailer Connected when Stepping on Brake Pedal with No Trailer

Published 09/30/2014

Question:

I followed the video to the letter, and found it very easy. I have one possible issue... When I press the brake, it does nothing. I have no trailer hooked up, but expected to see the no trailer light flash. This light does flash when I press the boost button or the manual know. Is this normal, or may I have a bad connection on the blue wire? There was also a fifth orange wire in the tow harness. Should this be hooked to anything?

asked by: Mike

Expert Reply:

The P3 brake controller # 90195 only uses the 4 wires. The 5th wire you are referring to sounds like the illumination circuit that is not needed by the brake controller. I am not sure though what the year, make, and model of your vehicle is.

You should get the no trailer connected message with no trailer connected when you apply the manual override but not with the brake pedal. Brake controllers like the P3 need to be moving (the vehicle moving with the brake controller in it I mean) so that it senses movement and then it would react with the brake pedal.

expert reply by: Michael H