OEM Trailer Wiring Troubleshooting Help

[cjett]

I installed the BMW oem trailer kit about 4 years ago in my 2003 X5 4.4. No issues until this past weekend. No lights at all on trailer. I also tried connecting another trailer and the same... no lights. Of course I'm 500 miles away from my full set of tools (including my volt meter), so, my testing has been limited to making up a bulb pigtail and checking for 12v on any of the pins and swapping the fuse in the trunk area (fuse looks fine, but, swapped with another 20 amp to be 100%). I also followed the wiring through the body into the spare tire area to make sure it wasn't cut or chaffed anywhere (everything looks good). The pdc is not disenganging either... so, the x5 doesn't seem to be "seeing" the trailer at all. Oh, and everything else in the car seems to be working fine (lights, etc)

Does anyone have a schematic, or any good troubleshooting tips? Thanks in advance.