brown wire

this may be a very dumb question, but I was having trouble finding a clear visual or description on what the factory entry point for the + lead into the fuse panel, brown wire, etc junction actually is. My car has 3 wires (2 from battery & brown wire to I presume ignition) joined with a wire...

Already done "Zonker's Mod" to Fuse A/1. Gauge reads from 10 to 16 V, normally in the center, 13 Volts +/-. Yesterday, I got caught out in the rain. #1 Put on Targa lid, Roll up windows and turn on FAN. Meter drops about a Volt. Raindrops on the windshield. Turn on wipers. Low barely...

With the dash out of my car, I am in the process of supplementing the brown wire (constant +12V) with a secondary 10ga. wire from the battery. This should improve things to all accessories that are not switched on via the ignition switch. This leaves me wondering how i can improve current flow...

I've been reading and researching many of the posts here regarding BWM, but for some reason I am having to fill in the gaps a great deal in order to apply the offered up knowledge to my 1978. My confusion and condundrum lies with the fuse 10 and fuse 12 locations always being referred to...