My L5030 has a white female plug inside the cab on the left side. At has a yellow and black wire running to it. What is the purpose of this plug? I see it in the owners manual drawing with no explanation.
If one wire is yellow with black stripe and the other solid black, best guess from looking at cabin wiring is a window defroster.
Some cabins have rear and both sides with electric wires in the glass. This may be the way a delux cab is set up.
If you don't have rear or side window defoggers, the glass can typically be purchased through wholegoods to gain this feature. Rear and side windows are separate p/n's.