Your car’s exterior lighting includes the headlights, parking lights, marker lights, fog lights ( if equipped), turn signals, hazard flashers, brake lights, centre high mounted stoplight ( CHMSL), taillights, back-up lights, and miscellaneous lamps. The exterior lights provide night vision and the ability to see in foggy conditions, as well as a means to signal other drivers about driving intentions and emergency situations.
The operation if your car’s exterior lights should be checked at every oil change to ensure your safety. Each year, have the alignment of your car’s headlights checked to make sure they’re aimed properly.
If one light doesn’t work in a circuit but the others do, the problem is probably a bad bulb.
If all the lights are out in a circuit ( except the headlights), the problem is probably a fuse, switch or other factor affecting the entire circuit.
A bad bulb or turn signal flasher usual- ly causes turn signal problems. A turn signals that flashes on one side, but not the other, is usually caused by a bad bulb on the side that won’t flash. If both sides don’t flash, and the bulbs appear to be OK, it’s likely that the turn signal flasher is faulty.
Check your car’s owner’s manual for fuse and turn signal flasher locations. Beyond that, it’s wise to consult a qualified service professional to diagnose other maladies in the lighting circuits. Upgraded halogen headlights produce a whiter light that is closer to the colour of natural daylight.
Whiter light provides drivers with improved night visibility which can help improve a driver’s reaction time and ability to see roadside objects at night. ( Car Care Canada)