Word to the wise... everything these guys asked you to check and verify could now be partially damaged, as a result of the broken wire you found... especially your ground wires having gasses and corrosion being generated. When your system undergoes stress from poor grounds, it can empty/dry out the end cells on your battery of acid/water, or all of them... verify your battery water levels, use Distilled... and clean all your ground connections, especially to the frame, firewall and alternator.
I had to do this yesterday for a guy who refused to verify his grounds, as asked, 12 months ago... his car was my ride home, so he got his car serviced and repaired in return for some Corned Beef and Cabbage...
Once the brown out starts, the effects can kill batteries, alternators, ignition modules and starters and they can all go in order or individually for months on end.
Clean your connections with baking soda, carefully, (don't spill baking soda water anywhere near your battery or BOOM) and sand and polish your terminal connections.
Use dielectric grease on everything... after you have cleaned and inspected every connection or connector.
...Or you MAY be posting here again in a few months.
Your problems may have only just started, unless you clean everything to spec, now you have found a poor ground and repaired it.
Especially at your starter connections, where the corrosion can and will accumulate where you may not see it.
Nice Rig!