I had the same problem. The first thing I did was, I took the two plastic pieces off the handle bars the first piece has five plastic screws, unscrew them a bit then pull them out then you need to lift it up and pry it off. The next piece has another four or five plastic screws/retainers and 4 regular Phillip head screws. Once you have that off, you will see the thumb warmer Just plugs in to the harness. Unplug it, get a volt meter set it to AC start the machine, turn it on and see if you have power. If you have power, your thumb warmer is burnt out. If you have no power, work your way back (switch, wiring). On mind, the thumb warmer was burnt out. The dealer wanted $50 for a new one, I went to our local snowmobile scrapyard and took one off a XLT and paid five dollars.