Battery/Alternator Charging problems

I recently did a front end rebuild, so basically everything from the firewall forward was removed, to paint the engine bay. Now that everything is re-assembled, I'm having issues with the alternator not charging the battery. The battery is brand new, as is the alternator. I also had it tested at 2 places, to make sure it wasn't defective. I also replaced the wiring harness that attaches to the alternator. I grounded it to the engine block.

I can't figure out what else it could be. The car will run, but clearly the battery is not being charged, and as soon as I shut her down, it won't turn over again, without being jumpstarted.

Any suggestions on how to troubleshoot this? Could it have anything to do with the voltage regulator or starter solenoid? I'm at a loss right now.

Ya, the headlights are real dim, and the directionals barely blink. voltage regulator, I hate that thing. I replace it almost every year it seems like. I'll try that.

And yes I re-attached the ground strap, but it's worth checking again, because I painted the block and the firewall, so I'll check the connections to make sure they are good surfaces.