Troubleshooting Vehicle 7 Way Connector with No 12v Power

Question:

If I apply power to trailer plug with 12volt battery they work but connect to the truck they don’t work tryed 2 different trucks and brakes work fine on other trailers I have on the same trucks? Completely all new brakes changed out the hole assembly’s. New trailer plug and wire to junction box. But like a said when applied 12volt power to plug no truck they work?

asked by: Jay

Expert Reply:

It sounds like the 12v power wire on your 7 way connection on your vehicle isn't connected to the battery or you've got a bad ground. Since you've tested the trailer on different trucks and everything is functioning correctly, you can isolate this issue to your truck's 7 way connector.

I would start with inspecting your vehicle 7 way to make sure that it is clean and free from debris on the pins. Next, you can go ahead and test your vehicle 7 way with a circuit tester like the # PTW2992 to see if all of the circuits are functioning-it sounds like the 12v power wire has been damaged at some point (start your test at the 7 way pins and work your way back, checking for voltage).

If you test the connection and your vehicle 7 way is functioning properly, please let me know and I will give you a few other steps to check out.

expert reply by: Erik B