I used a toggle switch and mounted it on the center console. When you take the console off you'll see the switch leads to a simple terminal connection much like in a computer. Very easy to wire up.
But with the toggle, the OD will stay off even after shutting down the car. When you start it back up, OD will still be off. You have to flip the toggle switch twice to renable the OD though. No biggie.
2004 ZX3 - Twighlight Blue_____________________________________ _ _ _ _ _ _