On the sportsman, the 04.5 and later do NOT have the purple wire. 04's and previous do. It's a hot-in-reverse wire. On the 04.5 and later, you can theoretically use the purple wire on the transmission sensor, which is ground in reverse, but that requires a lot of wiring (relays for power and diodes to control it).

 

On ’04.5 and up all you need to turn the work lights into Automatic Back-Up Lights is this.

 

Here is a old post for you guys that have question about the back work light mod....Caper.......