I've just read this whole thread, lots of good info going on, but the bike is in the shop where AC can't access it or learn from exploring its contents. How soon can you get it back? Winter is coming...
In the mean time, as a retired school shop teacher, I'm offering to send you one of those free meters we all know about, some led's , alligator leads, and a basic electricity book so you can start experimenting to learn about electric circuits. Then, you can use the color wiring diagrams in an old clymer manual to learn about the circuits on your bike and do the diagnostics contained in the clymer manual. When you get stuck, pictures and questions to the forum will get you back on track. You're in good hands with these guys ( they got me through plenty of learning curves).
So...pm me your address, ask the shop for your bike back and get started on this amazing journey.
p.s. I was able to use the clymer book to readjust my ailing voltage regulator and fix my charging problem.