Ironically we had what appears to be the same issue with our Journey this past weekend. Specifically, the Air Bag light would come on and there would be several dings, the light would go off, and then several minutes later, the process repeated. The interval between the on/off cycle varied. This would happen intermittently, maybe 4 or 5 times during our 20 minute car ride. This was on Sunday, on Monday the light did not come on at all.
My wife called the dealer Tuesday and spoke with a manager in the Service Department. He said the light coming on is a warning that the air bag will not deploy in the event of an accident, but does not indicate the specific reason. It could be as simple as a seat belt not being properly latched, or a loose harness under the seat. My wife had vacuumed out the car on Saturday, so, as the light has (for now) seemed to have stopped coming on, we are thinking she'd hit the wiring harness and loosened it. Or maybe it was a seatbelt issue. I'm checking all the cables and wiring under the seats to make sure it's all snug.