Run the wire(s) to the Power Distribution box next to the Brake master cylinder, there is a rubber bung, poke a hole in it and run the wire thru that and then it's inside the cabin.
Remove the lid on the PD Box and shine a flash light in there then go look inside the car under the dash and you'll see were the wires come in.

Also If you check my Gallery I have a couple of photos showing the wires going into the PD Box.

Hope this helps.