Troubleshooting a 2010 Toyota Prerunner W/ OEM Brake Controller That Activates Even When Set to 0

Question:

I have a 2010 Prerunner that has a factory-installed trailer harness including the brake controller plug-in behind the driver-side kick panel. I think I need to separate the turn signal/stop signal from a 4-way flat convert to 7 pin round as that seems to be affecting the brake controller signal. In fact, when the right turn signal is activated, the trailer brakes activate simultaneously with the signal bulb activation. Just very lightly touching the brake pedal squeals the RV tires Casita 17. Controller setting to 0.0. HELP Thank you!!

asked by: Bikerjim

Expert Reply:

Hey Jim, so typically when a brake controller is set to 0.0 that means the gain is all the way down, but the fact that the brakes are coming on still might mean that you either have some corrosion built up or damage to the 7 way, or there is a loose wire/short somewhere.

I'd start there before you go changing out things, because it could be as simple as cleaning off your 7 way or tightening a wire. If there happens to be a short, just replace the section, or entire wire, depending on the condition and check again.

expert reply by: Bryce D