Sorry for the lack of technical jargin, but I have a 2007 F-350 that I use to tow a fifth wheel around. Todat I got a message on the dash to "check trailer" Well, sure enough the outlet where I plug up the fifth wheel in the truck bed was dead. (no lights, breaks etc) and probably unrelated but at the same time noticed the door lock fuse had blown??? Anyway, check all the fuses I could find that had to do with the tow package and they all checked out fine. (I think I got them all) Finally, as a last resort I tried pluggng into the female end under the bumper instead of the one in the bed and it worked fine! Any ideas? I have my volt and ohm meter ready. Thanks in advance...
Judah

 

If the installer was doing his job right he used a plug cable that tapped into the factory cable using a male/female connector that intercepted the main cable shortly before it reached the bumper plug. The accepted way to apply this bed cable would be to unplug the main cable coming back from the cab, inserting the bed cable plug, then plug the bumper cable into that. But sometimes bad mechanics use a cheaper plug with just wires, Then they use crimp connectors or worse just cut into the harness, hook up the wires and tape it all back together. Check that connection first.