[Chesmu]

EDIT: Please see post #32 of this thread for an alternate wire pass-thru idea.
EDIT: Please post #38,#39 for Calvino's wiring update.

Now it's time to get dirty. Lift your car up and take off the driver side tire. In the wheel well you will see the access door that allows you to remove the turn signal bulb (see picture). Remove this access door and twist the white bulb holder counter-clockwise to remove the bulb. Carefully remove the bulb and replace with the LED. RE-install. Now look at the rear part of the wheel well and identify the small bundle of wires entering from the rear (cabin side). See picture. In this bundle are the sidemarker wires: blue with yellow stripe (power) and brown (ground).

Pick a color for your power supply (I chose green) and a different color wire for your ground (mine is black). You can pass these wires into the engine bay thru the very evident opening near the spring. Once the wires are in the engine bay, connect your ground wire to the ground wire (#2) FARTHER AWAY from the adapter than where your resistor is attached. Connect the power supply to wire #12 (the section of wire still attached to the headlight adapter) that you had clipped earlier.

Now replace the adapter on the headlight. Wrap your wires in electrical tape. There are multiple bundles of wire in the engine bay to attach the new wires to so they don't move around the engine bay.

Now put the car down and move to the other side....