Low voltage at gauge, no charge?

Actually I should have qualified. Most of us here do not do that bypass as shown. Rather, I usually mention it is a good overview to the what happens and why

Simply, bypass the ammeter by fastening the ammeter wires together or fix it by soldering the studs to the shunt and make sure the ammeter wires are "good," and fix the bulkhead connector terminals, either by replacement, or by running wires straight through the connector body.

Then after doing the above, run a BIG fused or fuse link protected bypass wire direct from the alternator output to the battery