Big thanks to Crom for putting this together. Great mod. Finally finished mine today. Very pleased except I scuffed things up when I drilled for my switch.
This isn't very organized, but I hope it makes this easier for some who are new to this like me.
My 2 cents:
This is a hard place to work. I’ve done a little of this sort of stuff, but the wire you’re tapping into is short and hard to work with. I didn’t see this until after I’d already done much of this part, but if I were doing it again - I’d do this:
I pulled the green/red wire out of the group to get some more slack to work with.
Then I just inserted a length of red wire to make it longer and even EASIER to work with.
Thanks to caribe makaira I used a 3m fuse tap which worked fine.
You cut the wire then put both ends in the tap and close it. The circuit is broken unless you insert a fuse. With a fuse in place the circuit is closed and the DTRL work just like normal. I put male spade connectors on the leads to my switch and inserted them in the slots for the fuse and now the switch controls the lights. I can pull the switch wires out and put the fuse in and I'm basically stock again.
It’s made for larger wire so I stripped mine before I closed it to make sure there was good contact. The spade connectors were a little to big so I trimmed them with some tin snips. They are close enough to one another that I worried they might touch so I put some electrical tape around one.
This is the switch I used:
Flush mount. Worked great. The terminals don’t look like the web site said.
This is the back of the switch:
I tested and found that attaching my wires to the top and bottom of the group of 3 terminals on the side that are unlabeled gave me what I wanted. In the normal state (switch not depressed) the DTRL are on. If you press the switch the DTRL go off. Attaching 12v to the two terminals labeled + and - lights the LED. I couldn’t find a combination that lit it based on whether it was pressed or not. I have no doubt that can be done, but I wasn’t sure I wanted it lit at all so I didn’t hook anything up for illumination.
This thread documents some of my prep work: