More Interesting Bits About Diagnosing A Tractor's Electrical System

I somehow managed to forget to post the follow up on the tractor. Until now. Lucky you!

Testing the alternator determined it was good (as was probably the voltage regulator). It turned out one of the wires to the regulator was bad. Upon close inspected it appeared to be smashed. It turns out it had melted. (Can you say "too much current"?). I ended up unwrapping the wiring harness and replacing a section of wire that had been melted. After wrapping it all back up, we jumped the tractor off a car (because the battery was dead). The tractor cranked and ran fine. White it was running I used my voltage meter to measure the alternator output and the battery voltage. The alternator output was fine and the battery was charging.

Using my twenty/twenty hindsight, it makes perfect since that a wire was bad.