Troubleshooting Brake Controller Installation Where Right Turn Signal Activates Trailer Brakes

Updated 09/07/2017 | Published 09/05/2017

Question:

I hooked up the prodigy P2 as instructed. all blinkers, lights, brake lights work fine, but when driving when I turn on the right blinker, the trailer brakes are activated. Where did I go wrong? Please advise. Thanks

asked by: Spud

Expert Reply:

The most likely cause for your brake controller to activate the trailer brakes when you apply the vehicle's right turn signal is a simple case of corrosion inside the 7-way socket.

If you refer to the linked photo of a 7-way you'll note that the right turn/stop light signals are carried on the contact at the 3-o-clock position. This contact is directly adjacent to the 5-o-clock contact for the trailer brake circuit.

The issue is probably due to corrosion inside the trailer connector (or trapped foreign material) that is causing the two adjacent circuits to be bridged together. When this happens the turn signal bleeds over to the brake circuit, causing the trailer brakes to engage.

The simplest potential fix is to spray an aerosol electrical contact cleaner, such as Caig De-Oxit, into the 7-way to dissolve the corrosion. It may be necessary to replace the 7-way if it is very badly corroded. You can disconnect the plug that connects to the back of the 7-way to get easier access.

Our various replacement vehicle 7-way sockets are shown on the linked page.

expert reply by: Adam R