Need help

Im trying to hook up Heat Demon heated grips to my quad.
i want to hook the power up to the cigg lighter plug..only because i hooked my winch up to the pink wire from the main group of wires..
I cant tell which wire, green or white, is the hot one. Ive tried a VOM and it wont register either way. Do I have a problem there as well?
Also, can i hook the ground to the other wire, or just to the body of the quad..
any help would be greatul…

Thanks