See this project posting; it shows where the wiring is. As I found out, just because there's wiring, does not mean your factory stereo will support a subwoofer.
You will also need the cable from the kick panel to the subwoofer - a very difficult find if you plan on using a factory sub. The part number/name is 1L5Z-18B864-AA, WIRE ASSY - AMPLIFIER.
