Is it the white / black wire? Going to add a fuse for constant power to add three way cigarette outlet adapter for cell phone and satellite radio. Which wire do I splice in to on the back of the lighter plug?
You definitely should get a multi-meter. If your intention's to have constant 12 volt power available, keep in mind: power is cut from the 12 volt sockets when the car's off for a reason: the 12 volt has a limited capacity.
Multimeters can be had for $1, so I second the advice above. That said, ground is the wire that goes to the outside of the lighter casing, and + is the wire leading into the center of the lighter plug.
