Lately, we’ve been spending a lot of time driving in the dark so it is important that our lights are in good working order.
How are yours?
To check, turn on your headlights and walk around the car. Obviously, you want to make sure both headlights are working, along with both amber parking lights.
Walk to the back of the car, checking your side marker lights. Some cars, particularly European models, have separate marker lights; others let the parking lights do double duty by wrapping the lenses around the corners of the fenders.
When you get to the rear, check that all the taillights are glowing with equal brightness.
Next, switch on the hazard (four-way) lights, but don’t turn off the headlights. Walk around the car again and see whether both parking lights are flashing brighter and the taillights are doing likewise. The filaments that makes the taillights flash brighter also serves as the brake lights. But the center-high-mounted-stop-light (CHMSL) should not be on.
If all the lights are blinking properly when the hazard switch is activated, chances are good that the turn signals are working, too. But there could be a problem with the turn signal flasher so try them–left and right. Remember to switch off the hazard lights.
Before you turn off the headlights, check the high beams.
This next test can be done with the headlights on or off, but it can be helpful to leave them on. Have a helper apply the brakes while you observe the brake lights. All should come on with equal brightness and the CHMSL (pronounced chim’ sel) should glow. If one taillight or brake light goes out while another gets brighter, chances are good that there is a ground problem in the circuit. You have probably been behind a car that has done this and found it puzzling.
If only one light of a group doesn’t work, it is probably burned out. If all lights fail, check for a blown fuse or circuit breaker before replacing a bunch of bulbs.
Bulb replacement is straightforward but getting to them can be a challenge. Most headlights are now capsules that can be accessed from behind when the hood is open. Unplug the connector then twist the locking ring (usually plastic) and remove it. Then, pull the bulb straight out without twisting.
Sealed-beam headlights, on older cars, are usually changed from the front. Sealed beams are held in place with a trim ring attached by screws. Just be careful not to turn the adjustment screws by mistake or you will mess up the headlight aim.
Many parking light bulbs are accessed like headlights: Remove the retainer ring. But not all bulbs are removed and inserted similarly. Most have a brass bayonet base with two nubs that lock into the socket. The nubs are at staggered heights to prevent the bulb from being installed incorrectly. Match the nubs with the slots when installing.
Other bulbs are the push-in style. Just pull them straight out. When installing, note the indexing tab on one side or the bulb won’t fit.
In the back, taillights and brake lights are often accessible through the trunk. You may have to pull aside some covers to get to them, though.
Though changing most bulbs is no more complicated than changing one in your home, occasionally one may be stuck–especially the bayonet type that you must push and twist at the same time. With too much force, the bulb could shatter in your hand, cutting your fingers. One old trick is to use a piece of rubber hose, which provides better grip as well as protection, in place of your fingers. Press the end of the rubber hose around the glass so you can push and twist at the same time.
When installing new bulbs, avoid touching the glass–especially on halogen bulbs. Oils from your skin can reduce bulb life. Also, be sure the lights are switched off before installing, as they can get real hot real fast.
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Bob Weber is an ASE-certified Master Automobile Technician, having recertified every five years since 1978. Contact him at motormouth(underscore)trib@verizon.net.
