Volvo Repair: faulty trouble lights, speed sensors, crash sensor

Question
I have a 2000 s80 non turbo. my wife was picking up food at a drive through resturant and the anti lock brake light and the air bag light came on. no collision whatsoever. I undid the battery and cleaned the post and the brake light went off but not the air bag light. also brakes and fluid seem fine.  

Answer
The brake system is very sensitive to differences in the speeds of the wheel speed sensors so sometimes just going around curves the wrong speed and angle can get the light to come on temporarily.  The only thing that will set the brake light is a wheel speed issue, or fluid level sensor.  The airbag light can be on for a few reasons.  

1) faulty wiring to crash sensor, or the sensor itself is bad.
2) faulty wiring to airbag unit (the units themselves are rated to go up to 20 years with out service, don't go bad)
3) faulty SRS module/module wiring

Thats it.  nothing else could be causing it.  Should still be covered under warranty though.  Saftey systems arent' under the same warranty as the rest of the car just like the emmissions systems.  Talk to your dealer and the should be able to take care of it for you.  Hope that helps.

James