2004 E350 (6.0), factory tow package.
I'm replacing an old Curt controller with a new Tekonsha. I patched the new harness from the Tekonsha (P3) into the old harness (black to black, red to red, etc.) Plug in the footwell is grey (the plug is supposed to be brown, but I don't see a brown plug after a long time looking, and 5 out of the 6 wires match for the F7UB-14A411 connector, the one difference is I have a white/red instead of a yellow), but the right location. With the key off, I plugged the new controller into the harness, and the right turn signal indicator came on solid. I can guess at a short between the turn signal wire (which doesn't go through the controller) and something else, but I thought that all of the four leads (positive, ground, brake and brake switch) would be controlled power wise by the ignition switch? Anyone have any thoughts on why the controller would close one of the circuits in key off? I need to get out there with a multimeter to start digging in, but I'm hoping on thoughts of what to look for. The Curt has been disconnected for about a year, so its possible that something changed since I last ran it. Maybe a relay stuck on for the tow power? Anyone seen this before?


Carl

 

Well, after another hour of looking at pictures and crawling under the dash, there is not only a grey connector with the correct shell behind the parking brake, but there is also a brown one, which somehow (even though I pulled the harness out last week) was somehow hidden behind the fuse block. No idea what the grey one is for, but the brown one works.