* Speedometers are unique in that some of them use physical cables instead of sensors, so a speedometer not working can also indicate a broken cable or stripped gear.
* If one or more warning lights fail to illuminate when you first turn the key on, it usually indicates a blown bulb.
* If none of the lights come on at all, check the fuses and wiring to the instrument cluster first.
* If a warning light comes on and stays on when the engine is running, that usually indicates a problem with that specific system.