Troubleshooting 2017 Flagstaff Trailer Lights Not Operating

Question:

Hooked up my 2017 Flagstaff trailer and no lights. Checked the truck female plug and tester lighted up, so must be problem with trailer. Checked fuses....ok. No corrosion apparent. Almost new cord...wiring etc...what could problem be? Checked online and could not see where any trailer light cords, boxes have inline fuse. Now wondering if not having my braked controller plugged in....could somehow affect the trailer lights? Trailer is now in storage and cant check if brake controller could be the reason no lights.

asked by: Joe L

Expert Reply:

If you tested the wiring connector on your tow vehicle and everything was working properly then the problem is definitely on the trailer side of things.

Start off by physically inspecting the connector on your 2017 Flagstaff making sure to clean out any corrosion or debris that may be present. After this check to make sure that all of the wiring is secure at the back of your trailer connector and that any wiring you can see is in good shape.

The next step is to check your ground connections. Poor grounds always cause light issues and they either need to be secured or cleaned and then secured. You can run them up to the coupler to make sure you get a secure connection that is also on a clean, bare-metal surface.

Your brake controller wouldn't be causing the lights on your trailer to not function because it is on a different circuit. What you can do to test your trailer though is use a 12V battery to test the functions of your trailer 7-Way connector. Ground the negative terminal and then use the positive terminal to test each pin to make sure it operates the correct functions.

I have attached some photos showing the pin locations on both a typical vehicle 7-Way and a typical trailer 7-Way. The wire colors don't always match so it is best to test for function. I have also attached a link to various lighting and wiring products that you can reference. Let me know if these tips don't help your issue and I can help you troubleshoot further.

expert reply by: Jon G