Dear friends
Also was thinking last Night, that this kind of improved rear defroster harness can be made as well for cars like w111 coupe and w108/109. Just need from the owner of the car project car instructions on where they want the switch to be installed and to confirm on which side of the rear windshield are the connections for the defroster.
As you may know I live in Venezuela an none of my cars came with factory rear windshield defroster, as it’s not needed on this tropical weather.
Regards
Lp