How would a driver know that a brake light bulb is not working?

There are a few ways that a driver can identify if one of their brake light bulbs is burnt out or not working properly:

Visual Inspection

The easiest way is to do a visual inspection of the brake lights. This can be done by having someone else step on the brakes while you look at the reflection of the lights in another vehicle’s windows, a storefront window, garage door, etc. Check that both brake lights come on and are bright. If one side is dimmer or does not light up, then that bulb needs to be replaced.

You can also use the reflection of the car in a parking lot to check the brake lights yourself. Just press on the brakes and look at the reflection to see if both sides are functioning properly.

Dashboard Warning Light

Many modern vehicles have a dashboard warning light that will illuminate if a brake light bulb goes out. The symbol is usually a picture of the rear lights/brakes. Check your owner’s manual to confirm what the warning light means in your vehicle.

Ask Someone

Have a friend or family member stand behind your vehicle while you press on the brakes. Ask them if both lights are working and bright. This extra set of eyes can help identify if a bulb is burnt out.

Mechanic Inspection

During an oil change or routine maintenance, a mechanic will often inspect all exterior lights including the brake lights. They can notify you if a bulb needs to be replaced.

Driving at Night

It’s easier to spot a burnt out brake light bulb when driving at night. Check the reflection of the brake lights in the cars behind you. If one side does not light up, then that bulb needs to be replaced.

Conclusion

Catching a burnt out brake light bulb quickly is important for safe driving. Regularly checking the lights yourself and having them inspected by a mechanic are good ways to identify any issues. Most drivers discover a non-working bulb when it finally burns out, either through a dashboard warning or noticing the difference in brightness on each side. Replacing brake light bulbs promptly can prevent an accident or traffic stop.