The easiest place to access the wiring that you would need to tap into is behind the tail light assemblies inside the trunk. Pull any carpet or lining away from the rear of the tail lights, and locate the wiring harnesses exiting the tail lights.
Start on the drivers side. Ground the white wire to clean metal on the inside of the trunk. If you can find a factory grounding point nearby, go ahead and use it. Otherwise, use a self-tapping screw. Then, have a helper turn on the left turn signal.... view full answer...