i've got my sat radio, gps, and radar detector all hardwired, the RD had it's own hardwire cord, the sat radio and gps don't make them, only cig lighter adaptors, radioshack sells a small 7dollar adaptor that turns those cig lighter adaptors into a 12v pos, and a ground, i use two of them, and 1 add-a-circuit, all hardwired into my rear wiper, which is a 20amp fuse normally, and my add-a-circuit for all those has a 1amp fuse powering those 3 and the original 20amp still for the rear wiper
occasionally when i first turn the car on if i enable the rear wiper for 'interval' wiping, it'll freeze once or twice, i just assume it's from the rd/gps/radio sucking a buncha power, after your driving for 1min or so, it fixes itself and has 0 issues
so you could easily do what you want, just goto radio shack and pick up what i said, can't find it online, but when you see the packaging you'll know it, just say you need a 'cigarette lighter to 12v power and ground', best 7bucks a pop i ever spent

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