Silverado Accessory Wiring

I am sure this is a simple questions for some of you pro mechanics. I have this 2003 silverado. I am attempting to wire in an auto dimming compass/temp/gauge. The directions state for power to tie into a switched power source. Other spots in this forum state that the 'orange' wire from the ignition switch is the accessory line. Would this 'orange' wire be the wire that runs into the fuse box in the back? Or - is there another power source/wire to use that is easy to find?

your ignition wires are the wires coming directly off of the key cylinder. there is an orange wire or brown wire you can use. they both will be heavier gauge wires.