electrical is baffling me-help!!

You could have a bad regulator

You could have a situation where the regulator is not really seeing the battery negative (ground)

You could have a situation where the "sense" (ign) terminal on the regulator is not seeing the battery voltage, due to a harness connection problem

to determine what's what,

Run the engine and make these tests first with the battery "up" first with all accessories off, and again with headlights, heater on, and the engine running at an RPM to simulate 'low to medium' cruise.

With the engine running as above, stick one probe of your meter directly onto the regulator case. Stick the other probe directly onto battery negative post. You are looking for a VERY low reading, the lower the better. Zero would be perfect, more thatn .2V (two tenths of a volt) is too much. If this is high, run a better bonding strap from the block to the firewall, or at least about a no10 from the block to the regulator mounting bolts. Make sure they are clean, and use star washers

Now check the positive end. You may have a voltage drop in the harness. Once again, with engine running as above, stick one probe as close as you can get to the regulator ign terminal (blue ignition run) and the other probe directly onto the battery positive terminal.

Once again, over .2V is too high. The path is the blue "ign run" wire, from the IGN terminal on the regulator, through the bulkhead, to the connector on the ignition switch, through the switch contacts, back out the switch connector, back out the bulkhead, to the main connection on the starter relay. ANY bad connection in this path can cause this problem

If both these check out, have the battery checked for a bad cell, and then change the regulator.

WHAT ARE YOU USING to determine the charging voltage, and where is it connected?