Switched Power? '05 TRX400EX

Switched power? '05 TRX400EX


Grip Heaters Any 'Install Tips'?
Ordered a set of grip heaters. From Rocky Mountain ATV
LINK>>Tusk Grip Heater Kit | ATV | Rocky Mountain ATV/MC

They will go under the hand grips of my '05 Honda TRX400EX.
I did a search, 'Grip heaters' and found nothing.
Has anyone installed this type on your Quad?
Any pitfalls I should know about/watch for?
I plan to use 'switched' power. Meaning when the 'key' is on the grips have power to them. Off and no power. That way I can't forget and leave them on and drain the battery. Or, a 'friend' can't mess with the bike and turn them on.

Where on the bike can I 'Tap-into' for 'switched' power?