Troubleshooting Trailer Brakes After 7-Way Disconnected Repeatedly

Question:

Trailer cord kept pulling out. Now trailer brakes not working but trailer brake lights are

asked by: Jerry S

Helpful Expert Reply:

It sounds like your trailer's 7-way plug has disconnected from the 7-way socket on your 2018 Ram and may have been damaged. If you can see clear physical damage to the plug (such as from it dragging on the ground) the easiest way to replace it is with a junction box kit like 7-Way Wiring Kit # HS381-9000. Includes a junction box, 7-way with cord and connectors. The linked article on trailer wiring will help you with correct installation.

If you wish to test the brake circuit on the Ram truck's 7-way socket you can use a circuit tester like # PTW2992 while a helper presses the manual override on your brake controller. Apply the tester ground lead to the pin at the 7:00 position and the probe to the pin at the 5:00 position; please see the linked photo. You should detect brake power on that circuit when the manual override lever is pressed. If you do not then the plug disconnecting over and over may have damaged the 7-way socket. If so use part # HM40975.

expert reply by: Adam R