Jeffery -

As long as the instrument warning lights can ground through the alternator rotor the batt light will stay dark. The light is on when the alternator is not charging at all. You may have weak brushes causing the low charge, or a blown diode.

Remove the brush holder/voltage regulator unit and check the length of the brushes. Under 3mm is time to replace. Easiest is to replace th ewhole unit, $60 - $70 at a dealer. Or, you can get just the brushes for under 10 bux and just solder them into the old unit.

Turn signal relay, the flasher relay, is p/n 1363788-3, used beginning in 1975 on 240, 260, 740, 760, 780, 940, and 960 models, except the 740, 760, 940 from 1988 on may have the switch included.

Get a couple from a boneyard and test them - it's easy to do - before buying a new one.

Good Luck,

Bob

:>)