The 12V (cigarette lighter) outlet in this USA zone car, is in the armrest pocket and is constantly on. We wanted to hook up a dash cam and an apple charging device that can work when the ignition is on, rather than all the time. After seeing a couple of ways to do this on-line, we settled for this easily reversible modification to the fuse box in the engine bay.
The mod changes the source of the power supplied to the outlet from constantly on, to a switched fuse. It uses a Bussmann device that adds a circuit to an existing fuse socket, which then supplied switched power to the 12V socket fuse - feeder wire side / not 12v supply side. A blown fuse is needed here, or drill a hole thru the middle of the fuse.
https://www.autozone.com/electrical-and-lighting/fuse-and-accessories/bussmann-atm-add-a-circuit-fuse-tap/32416_0_0
You also need longer mini fuses, not the low profile ones, like this
https://www.oreillyauto.com/detail/b/blister-pack-4152/accessories-16449/accessories---exterior-16767/exterior-lighting-16612/bulb-flasher-fuse-16457/fuses-16615/fuses-11492/8db92bcc5690/littelfuse-blister-pack-7-5-amp-mini-fuse/min75bp/4414588?q=mini+fuses&pos=13
To reverse this mod simply remove the wiring and reinstall the original fuses
