I gave up on making an adaptor for the chrome light housing and decided instead to make one for a rubber housing, here it is.
Made of black polyethylene, kinda clunky looking. Jony Ive does not live here. It does seem to work though.
I led the power and ground wires through one of the holes in the rear valence, up over and well away from the muffler, and through a grommeted hole in the heat shield. I do wish there was a better route. I used one of those black plastic electrical box to house the relay.
I used wire I had lying around, not conforming very well to any colour code. I did use a little bus, power is on the right, and ground on the left. I mounted the box onto the plastic “bulkhead” that the air intake snorkel connects to on the right hand side of the engine compartment. I tapped into the black/blue power wire feeding the right hand side back up light to provide the signal power for the relay.
I also put in an old back up beeper I had on my ’82 westy. I was a good thing to have when my son was young and I got used to it, so now it’s on the syncro, just lying in front of right hand side tail lights.
I took power from the alternator stud – NOTE – I have not installed in inline fuse on this feed line yet, one DOES need to be installed. I led a ground to one of the alternator housing screws.
Gack, I need to buy black cable ties. Tested, and works (beeper too).