Let me caution you DO NOT plug into the thumb hand warmers power.
You could if you had a battery draw from there but most likely you don't on the 500xc. That would still not be great cause as you draw the battery the thumb/hand warmers kick out to charge the battery.
The lights are on thier own power source and are a good source of power if you have no alternates use them, but still not a good circut to overload. loss of lights at night is a bad thing.
Polaris xc models have a separate power source that is key switched at the ignition and only have power 12vt. when engine is running. You can find these wires to connect to on the right hand side of the fuel tank behind the coweling. You may need a meeter to find the live feed it should be gray and a small stripe I think black or red. In any case from the factory they have caps on the end and just seem to be extra wires going no place. If you can't locate them let me know I will go and look at mine what color it was. Just too cold to run out tonight.
I found out the hard way of where to connect. heated shields are awsome but they can draw some serious power when cold too.