I have mine at the top of the windshield, just left of the rear view mirror. I took the flat (telephone type wiring) up, under the headliner edge (just gently tuck it up there), from there, ran left, down the A piller (take off the a pillar for this... real easy) and it will drop straight down into the foot well. From there... um... I got lazy

and ran it straight to the cig lighter and plugged it in. You can easily use an add-a-fuse or tap the cig lighter, but I got lazy when i first put it in and I don't smoke and realized that it doesn't bother me at all that it's using the cig lighter.
Good purchase! V1 is absolutely fantastic and has proven to me to be very VERY accurate and effective. I caught myself numerous times unmarked cop hunting in traffic
wait... forward arrow? so he's up there somewhere ... oh now it's rear arrow.. I passed him... ok a little more... NOW it's side arrow ... Turn head and wave