Hmmm, when exactly does it come on? If it happens at night, at idle, with the headlights, radio and A/C on, I wouldn't be too worried yet.
It could be a problem in the circuit for the light itself, and nothing to do with the actual electrical power system. Like the oil pressure, it's another symptom of the serious lack of real gauges in this kind of vehicle.
My oil line fix
My 100k stopped odometer fix
Brace for impact, I'm in a "modifying mood". Massive thread count inbound.