Ok - woke up this morning with a brainstorm. This has been bugging me for a while, and I hate to just let it go. Since the wire bundle attached to the connector in question comes out of the wall into the generator compartment, could it possibly have something to do with the remote start switch on the control panel inside ?? Since I don't really want to tear out the walls to find this thing, I pulled the remote start panel out, to check the wire colors. Unfortunately, only 2 (Brown and Green) were the same as the ones in the connector. Then a light bulb came on - looked some more up in the ceiling of the basement storage, poked around a bit behind some stuff, and finally found what looks like a set of factory splices for all four wires, but the red changed to orange, and the blue to yellow. Brown and Green stayed the same. That would account for the lack of red and blue in the remote, and presence of orange and yellow. Duh ! No wonder I couldn't spot the right four colors in my efforts to trace this. Don't know why Jayco changed colors, but they did. A quick continuity test confirmed these to be the same wires.
Bottom line - this is a remote start connection that apparently plugs into the accessory generator, which I don't have anyway. But at least I learned something. Thanks for all the educated guesses and suggestions along the line from this forum. You all gave me ideas that finally found their way through my foggy brain to the finish line.
2003 Ford F-350 V-10 Crew Cab 4WD Long Bed
2004 Jayco Designer Medallion 29 RLTS 5th wheel
Bill, Gayle, and Mindi (dachshund)
Retired at last !
Nothing is foolproof to a sufficiently talented fool.