Loosen both cables at the adjuster nuts. Break open the switch housing and you'll see how the 2 cables are routed around the inside edge of the grip. There are very small round brass things that hold the cables on,VERY carefully remove the brass thingy's (they will get away from you) and the cables will be free.
If I remember correctly, there's a snap ring on the inside of the switch housing. I don't think you remove it but depress it enough to slide the cable housing from the switch housing. Sorry, but it's been a while since I changed the cables on my Softail.