Floor board keeps getting wet

You have a water leak. The only way to pinpoint this, is to remove portions, or all, of the interior and water test. It could be from body seams, and you have no way of knowing the source, without creating some visual area. If it is not dirty, it is more than likely rain water. If it has a sunroof, check the drainage of the tray. Poor/no drainage is a common source of water entry.

With a leaking heater core, or a leaking heater hose, you would have a loss of coolant to go with it. I do not believe you have any heater hoses that enter the passenger compartment. In either case, you would have the loss of coolant, and a sweet smell, along with a greasy film from the steam on the windows. As far as the airbag light sharing some relation, if water has infiltrated the airbag control module(SDM or DERM), that would be about the only circumstance. I am not sure where in your vehicle the airbag module resides, but below the drivers seat, or on the center hump, is a common locale.