usually thoes mirrors are always hot so you wont have to turn on the keey s/w to light up a mirror find the hot side of the fues box its on of thoes labled ign 1 or 2 not sure but one of thoes is always hot I think there are 4 or 5 labled at the fuse box.
with a in line fuse you just need to run one hot wire to the mirror it grounds it self to the body or mine did
I ran the wire up the driver side A pillar
But here is what I should have done the interior lights are always hot and I think the door s/w is the ground for inter lights and you can tap into the wire for the rear inter lights at the center of the t tops
