How to Test Your Backup Lights by Yourself

reverse light
Test your reverse lights to be sure you're operating safely. Getty Images

Your car or truck's tail lights, often called backup or reverse lights, are important safety features. Illumination is provided by a simple bulb in each light housing, but these small bulbs throw off a surprising amount of light when you're driving in reverse, which is not only critical for you, the driver, but also for pedestrians and other drivers who might be in proximity to your car. That is why the lights' coverings are red, instead of clear. You see that color, you know to be extra cautious.

Some states require that your vehicle has working tail lights in order to pass inspection, while others do not. Yours should be functioning regardless of the requirement. Here's how to test the bulbs on your backup lights during the day and without someone to help you.

Engine Off

To test your tail lights, turn the ignition key to the "ON" position, the spot where all of the dash lights and the radio come on, but before you actually start the car. Now put the transmission in reverse and engage the parking brake. If you have an automatic transmission, you might have to press the brake to release the shifter (a safety setting). Once you have the car in reverse—and, again, the parking brake is on—get out of the car and take a look at the rear end. If you see two bright red lights beaming at you, all is well.

If one or more of your reverse lights is not working, you'll need to replace a bulb or two. Don't worry, we can show you how to do that, too. In most cases, it's simply a matter of unscrewing the tail light housing and replacing the bulb. Sometimes the wiring is bad. Either way, the fix is usually quick and easy.

Double Duty

In some cases, those rear lights are not simply indicators. Certain automakers have decided that backup lights should also act as spotlights to illuminate the area in back of a vehicle. General Motors, for instance, has done this on a number of vehicles, most notably their SUVs.

Now, your reverse lights are bright. They already do a great job of lighting up anything you're about to back into, run over, or navigate toward when driving backward. As soon as you put your vehicle into reverse, the lights come on, and you can see.

But certain GM vehicles use the reverse lights for illumination at other times. For example, as soon as the owner unlocks the car with their key fob remote, the reverse lights come on to illuminate their walk to the vehicle. While this courtesy feature does provide extra security, it can also mislead other drivers, who might wait longer than necessary for a vehicle to back up, only to discover that the driver and passengers are just now getting in the car.

Fortunately, this function can usually be turned on and off as needed. Just check your owner's manual for how.