If you feel you may have an electrical issue in your sled:
440-600HO/VES:
First, start by unplugging your main chassis ground. Most of the chassis have a single black wire in a small white plug down by the chassis wire harness and going to the CDI. It goes into a 10 pin black and purple plug/wire harness on the 600HO CDI and is the second pin in on one row accross from the blue/yellow wire. If you unplug it, it will eliminate all of the kill switches and a few other things that could be grounding out. Start your sled up and see if that fixes the problem. You will have to plug the wire back in or choke the sled to kill it. If that solves the problem then you probably have a bad kill switch, light switch, handle bar hearter or something else that is grounding out or wiring that has rubbed through to ground. If it doesn't solve the problem then it may be spark plug caps (they should test at around 5k ohms) coil (try a coil from another sled), Stator or CDI. Most of the parts are available on our electrical page or call us, we can get it.
ALL:
There are a lot of bad dimmer switches. If the power wire comes undone in the switch it can ground to the handlebars and kill the spark. Unplug it to test if your sled produces spark and runs.

Other possibilities are a melted or rubbed through wire harness (usually by the exhaust or under the hood. Check tether and all regular kill switches. On many production models there is also 2 micro kill switches in the throttle assembly itself which can be unplugged for testing. Most of the parts are available on our electrical page or call us, we can get it.