[boxhead]

In my following reply I am assuming you have had the car for a while and this is a "new" problem?
Also assuming you have not had any recent electrical work (ie fans fitted)

I would suspect you may have 2 issues.
1 : Alternator not charging, it sounds like the exciter circuit is working (light on dash), but the alternator is not being triggered, so I would remove alternator and have it checked and rebuilt (vehicles with 304 engine from memory would have a black unit that bolts onto rear of alternator (internal regulator), any competent sparky should have a test bench and be able to test your alternator.

2 : it would also appear your fans are wired direct to Alternator (or atleast the power supply to relay is), I would go through the fan circuit and make sure it has a relay fitted and that the relay power supply is via a fused supply from battery.