Charging Circuit

[GrymReaper]

So, I've been having battery issues on my 83 High Sierra. I thought I just had a short to ground and figured an easy fix was just to unhook the neg cable from the battery when it was parked and I'd get to it on spring break ( have a lot of classes currently). Well, the battery got run down nonetheless, so I did a couple tests and figured out a.) the alternator tests fine (I took it in to get bench tested), b.) I don't have a short (my timing light doesn't light up when hooked between the neg battery cable and terminal when the truck is off, and c.) my alternator is definitely not charging my battery (12.5 volts across battery terminals, running or not).
So...do any of you have any insight as to where I should start looking? The connector to the regulator in my alternator is chock full of grease, so i bought a new one and will install it tomorrow, but I have my doubts as to whether this will actually fix my problem. Should I be looking at my battery cables? Any other sneaky spots I might check? The alternator's definitely running the electricity when the car's running, just not charging. Also, my dash voltmeter doesn't read at all. Any help would be appreciated.