The winter has gotten the better of me and I've finally succumbed by investing in some heated grips. I'm now faced with my nemesis of 'wiring' stuff on my bike. I'm wiring it into the side lights (so that I don't have to worry about draining the battery by leaving them on) but can't work out which wire is + or -. I have a Blue wire with a red stripe and a dark grey wire.

Any help gratefully received.