When your light comes on, is your fan running? Does it smell or feel extra hot? I would be really concerned about where that 6 oz of coolant went and look for and fix this problem asap. The starter switch is not that uncommon to have to take it apart and clean it. Like Jim said, it could just be a short in the wires, maybe at the temp sensor, or the temp sensor itself going bad, that's where I'd start lookin after making sure of no leaks.
Oh by the way, this is a water cooled machine, the fins don't cool AppleSauce, oh may help in the cooling process of the coolant some, but wuthout coolant in the system, you'll smoke your motor.