Originally Posted by e3NiNe

cut the cigarette adapeter off of the neon light
strip some of the plastic casing off of the wire
ground the striped colored wire to the body of the car
run the other wire to an inline fuse (something you can buy @ radioshack)
from the fuse, run the wire to an inline switch (something you can buy @ radioshack)
mount the switch
finally, run the wire from the switch to a constant power source in your fusebox