How to Inspect and Replace Vehicle Lighting

The lights on your car, truck or SUV are of vital importance. They are one of the most crucial safety items, just like the brakes or steering system. While yes, if one light such as a taillight or headlight burns out, it's not going to mean you'll lose control of your car, it's still important in terms of your being able to see where you're going and others' being able to see you.

You'd think that, considering the importance of vehicle lighting, there would be more information on the subject. Maybe it's because the headlights or taillights on most cars and trucks rarely cause any trouble, if any at all. And if they do, many people automatically take the vehicle to the dealership or a service center to have the light replaced.

That's where we come in. Although vehicle lighting is paramount to safety, the inspection and/or replacement of the various lights on your car or truck are less involved than you might believe. When a light (such as a headlight or taillight) quits working on your vehicle, changing out the old bulb for a new one is, in most cases, very easy. Usually, changing the lighting on most of today's cars doesn't require many tools. In fact, the only tool that would be needed to change a taillight bulb in cars such as our long-term 2000 Ford Focus ZX3 is a Phillips screwdriver. No tools are needed to access the headlights. There's only one screw holding the taillight housing to the car. The inside thumbscrew is accessible from inside the back of the car and can be turned with your hand, as we illustrate in the following photos.

Accessing headlights is even easier. In fact, changing a headlight in your car or truck isn't that much different from replacing a light bulb in your home. Take a look at the photo sequence of our hot-selling Focus below to see how little hassle it really is to replace vehicle headlights and taillights.

1. The inspection of vehicle lighting begins with the periodic checking of operation. Of course, headlights are easy. For taillights, you might need someone to stand behind the vehicle while you operate the running lights, brake lights and turn signals. You can also check for the function of these items by backing the vehicle up near a window and looking at the reflection through the back window. Your car's owner's manual is one of the most important tools for replacing vehicle lighting. You don't need to run off to the dealership just to replace a taillight, headlight or any other light in your car. Merely take a look at the manual, and it will tell you how to access the lights and the type of replacement to acquire. Most auto parts stores stock a full line of vehicle lights.

2. If a taillight or brake light (almost always the same bulb) isn't working, you need to access it for replacement. On some cars, you can get to the taillights just by pulling the socket out from inside the trunk. The Ford Focus hatchback has one screw holding the light housing in place on the outside. It's accessible by opening the tailgate.

3. Inside the storage area of the Focus, there's one plastic thumbscrew holding the housing in place. Once that's removed, the housing separates from the car. On Focus sedans (and many other cars) you don't even need a screwdriver, as the taillight housing is held in place with three thumbscrews that are accessible inside the trunk and easily come off using your hand.

4. With the thumbscrew and Phillips head screw removed, the entire housing lifts up away from the car.

5. To access the bulb in the housing, simply turn the bulb socket counterclockwise as far as possible and pull it out of the housing. At this point you can inspect the bulb and see if it's burned out. If the filament is broken, then the bulb needs to be replaced. To remove the bulb from the socket, hold the socket with one hand and pull the bulb out with the other. Some sockets require that you turn the bulb to remove it. This type of setup has notches in the socket, and the bulb is keyed with tabs on the base of the bulb so it fits in the socket only one way. Most newer vehicles, however, are simply a plug-in setup.

6. The standard taillight (or running light) and brake light are contained in the same bulb. Both filaments are visible here for both functions. If one of the two filaments is broken, then the bulb needs to be replaced.

7. At the front of the Focus are the headlights, sidemarker lights and optional driving lights. Replacing the headlights and sidemarker lights is a snap. No tools are required.

8. Access to the headlights is from under the hood. The plastic bulb cover rotates counterclockwise and comes off in your hand.

9. The headlight is a bulb unlike a sealed-beam lamp as used in older cars. With a sealed-beam headlamp, there are usually two or three screws and a ring around the headlamp that hold it in place. Once the light is removed, it unplugs much like the bulb shown in these photos. Getting back to the headlight bulb shown here, it removes and installs much like a standard taillight bulb. The three-pronged setup makes it so the bulb will only install one way. Simple and foolproof. In the Focus, there's a wire clip that holds the bulb in place inside the headlight housing. It swivels out of the way for removal and reinstallation.

10. The filaments in the headlights are similar to those in a standard taillight. There are usually two filaments — one for the lowbeams and one for the highbeams. If your car has separate lights for high and low beams, then there will only be one filament inside the bulb.

11. Access to the sidemarker lights is under the front fender. Simply hold on to the socket and turn it counterclockwise to remove it from the housing. Inspection of the bulb is the same as with the others. Check to see if the filament is broken. If so, then a replacement will be necessary.

Other Types of Vehicle Lighting

Your vehicle owner's manual contains a wealth of information concerning the inspection and replacement of lighting. The list of exterior bulbs to keep an eye on found in the Focus owner's manual is applicable to almost all cars and trucks. It says to check the operation of the following frequently: headlights, taillights, brake lights, high-mounted third brake light, turn signals (front and rear), backup lights and license-plate light. The Focus owner's manual also provides a chart with the trade number for the right bulb for all the above-listed applications, in addition to the interior dome light, map lights and luggage compartment lights. The Focus owner's manual contains information on how to replace various secondary outside and interior lights, as should any good automotive owner's manual. If you don't have a copy of your vehicle owner's manual, you can order a replacement from a local dealership that sells your make of car or truck.