electrical gremlins are back

Frankly I think you should have found the problem first. Introducing new problems with an (accidently improperly done) modification is no fun.

The main fail points in these cars in no particular order are:

Poor connections in the bulkhead connector
Poor connections at or IN the ammeter
Poor connections or failing ignition switch and connector
Poor connections in the fuse panel
In rare cases the welded splice (see MAD) this is a factory splice a few inches away from the ammeter in the black wire, up under the dash
sometimes the fuse link corrodes inside the insulation, causing problems, and intermittent connections.