Your Vehicle's Exterior Lighting System

Since the invention of the automobile, exterior lighting has been an important and necessary vehicle subsystem. Exterior lighting is vital to driving in the dark, driver and passenger safety, comfort, enjoyment, and even vehicle styling. The technology used in automotive lighting has rapidly increased to make lighting more automated, responsive, efficient, durable, visible, safe, and aesthetically pleasing to drivers and passengers.

The lighting system on a vehicle consists of lighting and signaling devices mounted or integrated on the front, rear, sides, and in some cases the top of vehicles. Exterior lights may consist of headlamps (low and high beam), park lights, daytime running lights, fog lights, signal lights, side marker lights, cab lights, tail lights, brake lights, center mount brake lights, reverse lights, and hazard flasher lights. These lights illuminate the roadway for the driver and increase the visibility of the vehicle in any position, allowing other drivers and pedestrians to see the vehicle's presence, position, size, direction of travel, and the driver's intentions regarding direction and speed. The operation of your vehicle's exterior lights should be inspected at every oil change interval to ensure your safety and the safety of others.

The most common problem with exterior lights is burned out bulbs. If one light in a circuit doesn't work but the others do, the problem is likely a faulty bulb. If all the lights in a circuit are not working, the problem may be a fuse, switch, wiring, or other factor affecting the entire circuit. A bad bulb or turn signal flasher usually causes turn signal problems. A turn signal that flashes on one side, but not the other, is usually caused by a bad bulb on the side that will not flash. If both sides don't flash, and the bulbs appear to be okay, it's likely the turn signal flasher is faulty.

Always replace defective bulbs with another bulb of the same exact type. During replacement, be careful not to touch the bulb itself as the oil from your skin can cause the bulb to fail prematurely. It is a good idea to wear latex or nitrile mechanic's gloves when replacing bulbs.

Exterior vehicle lights are components that sustain daily wear and tear, causing the need for regular inspection, maintenance, and periodic replacement. Bulbs that are blinking, dim, or burned out should be replaced immediately, and the electrical sockets should be closely inspected for corrosion and damage. Grit, rocks, bugs, and road debris constantly hit light lenses at high speeds taking a toll on the condition of plastic and glass. The sun and exposure to the elements will also cause plastic lenses to fade, discolor, crack, deteriorate, or to become hazy. Inspect your lights regularly for any of these signs and make necessary replacements when needed. Physically inspect and try to move light housings to make sure they are secure and do not have damage. Inspect for evidence of water intrusion which would indicate possible flood damage, faulty seals, or holes in lenses.

Be sure your front and rear lights are clean and clear. Wash your vehicle regularly to help keep lenses in good condition. Use a damp cloth or towel to wipe away any obstructing material such as dirt, dust, animal droppings, insects, and mud. Polish and restore lenses that are obstructed by hazy or cloudy surfaces. Replace lenses that are damaged.

Improperly aimed headlights can blind other drivers and hinder your frontal vision on the road. Frequently being 'flashed' with the high beam lights of other drivers is an indication your lights are aimed too high and may be obstructing the vision of other drivers. Check the aim of your headlights to ensure they are pointed in the right direction. To check if your headlights are aligned, pull up to a garage door on a level surface, turn the headlights on and compare the height and general position of the reflection of the two lights.

Headlights are not only intended for use while driving at night. Turn your lights on during storms, fog, dusk, twilight, evening hours, and even during the day. Headlights not only help you see, they help other drivers see you, as well.

When buying a used vehicle, have the exterior lights closely inspected to verify proper operation, alignment, and lens condition. A qualified technician will be able to give you the peace of mind that your vehicle is ready to operate at night, and that the signals you are giving to other drivers when braking and turning are providing safe and reliable driving messages.