We have a small camp trailer that we pull with our Toyota Highlander. I recently pulled it 600 miles with no problems. Then last week the trailer brakes quit working. The controller gave me an OL light which means a short in the system somewhere. I tried the trailer on the pickup and it worked ok. I then plugged a different trailer into the Toyota and got the OL light. That pretty well narrows it down to the wiring in the car.
I went over it repeatedly and couldn't find any shorts between the controller and the light plug. I finally ran new heavier power and ground wires the whole way. Same problem. The plug was new this spring, Hopkins brand. It took a bunch of time with a multimeter but I found that it was shorting inside the plug. It's a factory defect that sent the power from the brakes to the right turn lights. I had another new in the box Hopkins plug so I swapped it for a new one. Same problem. Hair tearing time. What are the odds of getting 2 factory defective plugs at the same time, but that's what I had.
I had yet another Hopkins plug that was in good shape. This one wasn't new but it was a more expensive type with the wires molded in so no screws are involved. It's just attaching the car wires to the plug pigtails. This time it's working again.
I wasted many hours tracking the dang thing down. The problem is that the blades in the plug wear through the rubber between them and the 2d one I tried was broken through from the factory. Hopkins is pretty low on my recommended company list right now.
