I just checked my '07 900. Wiper was installed by the dealer w/hardtop. I have the original installation instruction which identify's the wiper using an in line fuse. What it doesn't identify is the exact location of the 12v connection. On my unit that connection point is under the hood, near the r'frt shock tower. The in-line fuse shape is cylindrical and balck in color w/red wire. The fuse is a glass BUSS type, 8 amp. If the fuse is good (ck w/ohm meter), then I suggest ensuring there is power at the pick up point. Easily done w/a 12 volt test light or DVOM. Just remember to test w/ignition on. The wiper should be a switched accessory. If there is no power, then head to the fuse box at the back of the cab. Test all the fuses.
Hope that helps.