Peugeot 406 - KingKwabi
I have a mixed bag of electronic faults on my Peugeot 406 sedan. It's a 2.0L petrol from 2003. Here is a brief summary of the faults:

1. Speedometer stops working intermittently. It will stop working while driving and start again of its own accord. The odometer also drops off while this happens and won't read any mileage until the speedomter starts working again. Also the speedometer sometimes will be reading like the car is moving when I'm stationary and the car is idling. Weird, uh?
2.The air bag warning light will come on for no reason. It happens soon after the speedometer drops off. Interestingly, most times, that light has to come on before the speedometer starts working again. Coincidence?
3.When starting the car sometimes, the engine won't turn over and the dash clock resets itself, like it's a battery failure. If I try again it starts fine but the clock goes to all zeros and has to be reset. It usually happens after trying to restart the car after driving a considerable distance. Doesn't ever happen when trying to start the car first thing in the morning so I don't think it's the battery. The frequeuncy of this happening is increasing. At first it was just annoying, now I'm starting to get worried.

I think they all may be related. Like a busted relay, or a short or whatever. Can someone please give me a clue.