thats funny, i have an 03 summit 550f and got the same problem, bought it used, and just thought the light bulbs were burnt out, bought a pair of bulbs for 50 bucks not knowing the bigger problem, put um in looked great reved it up, pop, pop, and the hand warmers got super hot....
hooked up a volt meter to the wires, at idle it was at about 12-13 volts, little bit of throttle and it spiked to 50 volts,
ordered a new voltage reg, for bout 179 and put it in took no time at all and the problem is fixed....
BUt make sure you check every wire in ur sled as the voltage reg usualy goes bad cus of a short... look under the seat, thats where my sled had the problem, wires were stripped a bit, and thats what fried it.
i fixed that before i did the regulator..
hope that helps