Low charge to no charge issue pulling hair out

So i just did some extra tests. I disconnected the ammeter wires and married them together turned lights on and same result, 1 point drop 11.7 to 10.4 so from the interior bulkhead connector all the way to the back of the alternator. I checked all the other junctions in photo above except headlight switch and ignition switch.

Something odd however when i was hooked up normal i had 9.8 to battery side of fuse block with lights on where as the bulkhead and ammeter matched at 10.4 all from 11.7

So what i know is battery to bulkhead engine compartment side goes to 11.7.

Red wire on ammeter and firewall interior side bulk head is 10.4

And rear battery “red wire side of fuse block is 9.8.

Whats dors all this tell me for narrowing