Dash Light Warning Problem
 

Without warning, both the SRS and ASL dash lights come on and go off simultaneously. This can occur at idle, or on the highway - speed does not seem to be a factor and the time spent 'on' is random. When the lights are on, the engine idle increases from 500 to 2000 rpm - at low speeds this becomes interesting! Any suggestions re where to start looking?

What model and year car?