Hi, I'm looking to add power supply for a ham radio off of an empty location in the fuse box.
2001 cavalier
How would I do this?
Thanks!

Maybe look for some harness that will let you get power from factory radio wire.

There are fuse add-on's available at just about any auto parts store that plugs into a fuse location and has 2 fuse locations, one for the existing and one for the new tap. You could also just run a line from the battery directly with an in-line fuse.

If you're going to add a HAM rig transceiver, you don't want any voltage drop.
IMHO, go directly as possible from the positive terminal of the battery and from the negative battery's chassis connection for best transmit quality.
My Icom during SSB modulation peaks transmit current approaches 30 amps.
Excessive voltage drop will muddy and distort your transmit audio quality and cause band splatter as well.
Power cables are not a place to make shortcuts.

N7ZVX
Advanced ticket
Whidbey Island WA