The supplemental occupant restraint / air bag system continuously checks the circuity in the system for continuity. It does this by measuring the resistance in the circuit. If the resistance varies more than a set amount, the system knows there is a poor connection / excessive resistance or, more likely, a break in the wiring which would render part of the system inoperative.While driving down the freeway on my way to work at about 65 mph, my air bag light came on. After the ding and a few seconds it turned off. Then about 30 seconds later it did the same thing.
I would suspect the clock spring wiring. There are several circuits in the clockspring assembly and it is probable that the air bag system has the broken wire which is making intermittent contact. The air bag system uses connectors with gold plated pins so as to prevent corrosion problems.
The speedometer problems is an electrical connection issue. There is no link between the speed sensor and the air bag system. The instrument panel cluster needs to be removed and the electrical connector to the panel checked for cleanliness.What's interesting about it is during one point I witnessed my speedometer go from 68 to 0 back to 68 again, as if it was resetting itself. It only ever did that once. I was thinking maybe speed sensor issue could be telling the airbag computer something to turn itself off?