I can only tell you that the wiring loom, at the entry door (for wiper motor and door switch) are a common problem area, on 4440 tractors {= dome light doesn't work.}

They say the constant opening and closing of entry door, flexes that wire loom, and causes a break in the internal wires(inside harness).

Had it happen on our 4440, and later, was told it was a common issue, by JD mechanics and JD parts guys.(Wish I had known that, earlier, because it would have saved some trouble-shooting time)

Edit: I just read your other reply = I guess a 4430 is different.