Troubleshooting Jerking Trailer Brakes When Starting Up After a Stop

Question:

I have a 25 foot Jayco Travel Trailer my wife and I recently purchased. Our first venture with a full size trailer after pop ups while the kids were growing. I had a Pilot proportional brake controller installed on a 2004 Chev Avalanche for towing. We have now used it on several weekend trips. Brakes seem to work fine, everything feels OK when braking and the truck/trailer stop smoothly. My issue is after coming to a full stop at stop sign or red light. When I release the brake pedal on the truck, it jerks as it starts forward. It feels like the brakes are continuing to hold for a fraction of a second after the truck starts moving, then releasing causing a lurch. I have found if I reduce the power setting on the controller it helps quite a bit. The higher power the worse the jerk when releasing the breaks. Is the nature of proportional controllers or do I need to have my controller and/or trailer brakes checks? Thank you.

asked by: Steve M

Expert Reply:

If you are using the Pilot time-delay brake controller # 80550 what you are feeling with the brakes holding on after the pedal is released could indicate a malfunction inside the controller or potentially some kind of wiring issue that is letting 12V power reach the brake circuit even after the pedal is released.

If you have a circuit tester like # PTW2993 it is simple enough to test the truck side of the equation. Have a helper sit in the truck and press the brake while you have the tester applied to the brake circuit contact (at the 5-o-clock position on the 7-way socket - see linked photo, please). If you detect a brake signal without the brake pedal applied, then you need to replace the controller. If you find normal operation at the truck, then inspect the trailer wiring all the way from the 7-way plug to the brakes.

Corrosion in either the vehicle or trailer connector or damaged wiring on the trailer could cause one of the other circuits, such as the 12V auxiliary power feed for the trailer battery, to bleed over to the brake circuit. This could cause the brakes to remain energized. If the issue is a loose/damaged wire on the trailer, the motion of the trailer could cause this to occur only at times when you re-start after a stop. Something as simple as worn insulation in the trailer wiring could cause this.

If you do need a new controller go for a proportional type unit such as the Prodigy P2 # 90885. This unit is reliable, easy to use and it lasts. To install this in a 2004 Avalanche all you need is wiring adapter # 3015-P which plugs in under the dash as shown in the linked video.