Help! Battery light on, glow out.
 

Ok, before I drop a few hundred $$ can someone let me know if I'm right on all this: My glow plugs died the other day (see thread "glow light") Then the battery light came on with the key out. This drained the battery and now its cold so I cant get the thing to start.
I changed #5 plug with #1 to see if #1 was throwing the system off. nothing. Then I attached another wire across the 80amp fuse just to see. still nothing.
Only 1 semi-local place has used relays, and then only $15 cheaper than fastlane. So, before I place a fastlane order, is it the relay? And why is it shorting the battery?

Thanks,
Paul

update
 

ok, here is the latest. I followed a tip from a thread to the alternator. when I disconnect the wires to it, the battery light goes out, and she starts right up (with a jump, of course). So, this probably means that my glow plugs are working fine (its 40F today). Now, is it the diode in the alternator, thus the need for a new unit, or is it the sensor thing that I can just get new brushes for?
Paul

82 300D (t)