I have a 14 Slim. After doing my homework and looking at the HD manual wiring schematics I was lead to believe they were hard wired to the hand controls. I bought everything needed to do this, 6 pin connector, pins, wires etc. Prior to cutting the wires I pulled back the tank to expose the 6 pin connector to my surprise it had both male and female sides and wires that ran up to the handlebars. So If you have a Slim look under the tank first before you buy unneeded stuff.

For the job you will need at least 2 inches of 5/16-24 thread weather it's on a bolt you have to cut off the head or some all thread stainless is preferred . No one carries either in my area. A member mentioned using carb studs. I got some 2 3/4 ones from Pep Boy's for $10. Also picked up some disc brake bolt covers for 2.99. You don't need the $10 ones.
Carb studs - whack off the coarse portion of thread and little metal tit on the other end so all you have remaining is fine threads. You will also need 4 nuts and 4 washers. The carb bolt kit has them all.

So lift the tank and depin one side at a time. It was easier for me to keep track off. Moving the wire back and forth I was able to pull them out of the bars. Remove the hex head screw from the fork leg use thread locker and screw in the stud. Add a washer and nut, tighten. Add rubber boot then another nut and washer. Roll on turn signal then tighten up. A few zip ties and all was done.