Originally Posted by DeusExMaxima

Ok...I figured it out. This procedure is to hook up the JDM foglight as a brake light. It can be used to hook up the light as a running light too or whatever you wish. The key is that no external harness is necessary. It's already in the car.

The process is as follows:

1. Pull the trunk paneling away
2. Locate the wires going to the brake light assembly.
3. Pull back the electrical tape and expose the wires of both the subharness going to the rear and the wires running to the brake/tail light.
4. Dig in the harness and pull up the yellowish wire.
5. Cut the wire. This is the key since it runs to the BCM.
6. Join the yellowish wire to the green wire coming from the brake light. Either solder or butt connector.
7. Plug in your fog light to the oem connector.

You now have a 4th brake light without using an outside harness. The ground wire is already grounded. You don't even have to remove the tail light.