Various kinds of bulbs are fitted to the complete range of vehicles and, when renewing a bulb, it is important to use the correct voltage, wattage and type. Typically, the voltage and wattage are stamped on the bulb base or glass. A bulb that is marked 12v/21w, for example, is a 12-volt and 21-watt bulb. A dual filament bulb used in stop/tail lamps. It is actually two bulbs in one base. For example, a marking of 12v 21/5 means that the bulb has a wattage of 21w for the stop filament and 5w for the tail filament. To test bulbs, remove them from the holder and connect jumper leads to the battery. If illuminated, the bulb is fine but otherwise should be replaced. To renew the headlamp bulb, disconnect the wiring, take off the dust cap, unclip the retaining clip, and pull out the bulb without touching the glass. The bulb is secured, and the headlamp is checked. To renew the bulb of the fog lamp, remove the lamp, withdraw the bulb and check the proper sealing ring seating. To adjust the headlamp and fog lamp aim, park the vehicle over level ground and unladed condition. Then use the aiming equipment or a board to mark reference lines and adjust the beams as per the local regulations. Various lamps such as front park, turn signal, side turn signal, rear combination, high mounted stop, number plate, reverse and courtesy lamp have generally pretty similar and straightforward procedures to take out wiring and covers and ensure contacts are clean. After that, you can install a new bulb.