Boot Popper Wiring...

[Chris]

For my interior one I used a heated rear window switch, popped off the frosted cover, sanded off the transfer then put it in backwards.
This was mounted below the headlight adjuster next to the airbag cut off. I used an ignition live from the headunit to power it also.

For the external one I'd take a feed straight from the rear light so when its getting power to be illuminated it will power the external switch.
It may be worth fitting a diode in line to prevent the current flowing backwards.