How do you run a switched 12 volt wire from fuse box to new radio on a 2007 Saturn Ion?

To run a switched 12-volt wire from the fuse box to your new radio in a 2007 Saturn Ion, first, identify a suitable fuse in the fuse box that is only active when the ignition is on. Use a fuse tap to connect a new wire to this fuse, ensuring it has an inline fuse for protection. Route the wire through the firewall and into the cabin, following existing wiring paths. Finally, connect the other end of the wire to the appropriate switched power terminal on your new radio.