Troubleshooting Taillight Wire Power at 7-Way Trailer Connector

Question:

I just replaced the OEM plug at the rear of the 2000 Suburban and the contact for taillight is hot when no taillight are turned on on vehicle. All lights function properly on vehicle and all other trailer circuits are working. This is why I replaced the 7 prong plug, so I put the OEM plug back on vehicle and it is doing the same thing. It is not the plug as I tested the wire and it is hot at the wire harness end. Any ideas?

asked by: Bob

Expert Reply:

What pin of your 7-way are you testing? If you are testing the pin at 11 o'clock when facing the connection on your truck, you should have a reading anytime the truck is turned on for running lights unless you have turned off the running lights. All other plugs should be cold except the 12V at 1 o'clock. Use a multi-meter like # PT89ZR to check for the voltage reading so we can further troubleshoot. Is it illuminating the stop lights on the trailer or the running lights?

expert reply by: Jason S