My newly purchased '89 300CE isn't charging. 12.5V at the battery with engine off, 12.0 with it on so the alternator isn't supplying juice. I replaced the voltage regulator because the brushes were worn to nubs, but that didn't help. The battery indicator light in the dash isn't coming on with the ignition - in fact none of the lights in the instrument cluster are coming on except SRS. I pulled the cluster and checked the battery bulb and it's fine (6 ohms across contacts and it lit up when I touched it with a 9V battery).

I'm about ready to buy an alternator, but I wonder if something else is going on since the idiot lights in the cluster aren't coming on. Any suggestions?