should come on when I turn the key on? All I get is the glow plug light, which cycles normally(I think)

Also, I have a new(rebuilt) alternator that at idle only shows 12.25 volts on a good voltmeter. I searched and I see where that should be 14.4 volts, right. Battery is also new.
I'm going to clean the alt connector next. One post said to ground alt to body, is that an external ground?
PO really had the wiring screwed up and I'm trying to sort it out. No wipers, but whunter said I could run a fused jumper for now.

I have 2 color fuses, red and white, which amps is which? does someone have a sketch/diagram of the fuse box which shows the different amps?

I have always wanted a diesel MB and after some initial discouragement, I've almost got her on the road.

This is an 80 300D, unknown miles(at least 184,000), unknown history.

Thanks,
Dave