One Brake Light Not Working But Bulb Is Good (Causes And Fixes)
If one of your brake lights goes out, it’s common sense to replace the bulb as it’s one of the most common culprits behind this problem. However, a new bulb doesn’t always solve the issue. And this may leave you wondering—what else could be causing the brake light not to work but the bulb is good?
One brake light not working but the bulb is good can arise from a variety of issues such as using the wrong bulb, a wrongly installed bulb, a defective socket, a blown fuse, wiring problems, or a bad ground connection.
This article covers more comprehensive details about one of your brake lights not working even after changing the bulb. We’ll discuss all the common causes behind this issue and offer you tips on how to troubleshoot and fix this problem.
One Brake Light Not Working But The Bulb Is Good Causes:
When dealing with a situation where one brake light is not working but the bulb is good, you should consider the following factors as the potential culprits behind this problem:
You have the wrong bulb
If you put the wrong bulb in the socket, it will not work. Instead, it may end up blowing the fuse, leaving you with more problems to fix.
Confirm if you have the correct replacement bulb. For instance, if your car uses a dual filament bulb and you replace it with a single filament type, it won’t work.
Also, the new bulb you just installed could be defective. Try swapping the bulb from the working light to the malfunctioning one and see if it works.
The bulb is wrongly installed
The bulb itself may be good but if you install it incorrectly, it also won’t come on when you press the brake pedal.
If you’ve already confirmed that power is reaching the bulb socket (more details below), try removing the bulb and reinstalling it correctly, making sure it sits properly in the socket.
Defective socket
A defective socket may lead to a bad contact inside the socket causing the light not to work.
The contact inside the socket may be bent thus making bad electrical contact with the bulb, and causing it not to come on.
Simply pulling this contact outward can help create a good contact with your bulb and the problem is solved!
You should also inspect the contacts inside the bulb for corrosion or damaged contacts and clean them to see if it solves the problem.
If the socket has damaged contacts, you may want to replace it with a new one.
Wiring problems
If you have damaged or worn wiring leading to the malfunctioning brake light, it could also be the reason the light is not working.
In this case, you should inspect the wiring harness connecting to the brake light for signs of damage, e.g. fraying, cuts, and loose connections.
These issues can disrupt the electricity flow, preventing the bulb from getting the power it needs to illuminate when you press the brake pedal.
Exposed wiring could also be causing short-circuiting and making the light malfunction.
Bad ground connection
The ground connection for the affected light can also cause it to malfunction. A poor ground connection leads to an incomplete circuit, resulting in the disruption of electricity flow to the brake light.
Inspecting the ground connection point for dirt, corrosion or loose connection can help resolve grounding connection issues.
NOTE: Since the other brake light is working, you can rule out some issues as the causes behind one light malfunctioning. These issues include a blown fuse (both brake lights will be affected if a fuse is blown), a bad brake light switch, and other parts of the brake light switch shared by the two bulbs.
How To Fix One Brake Light Not Working But The Bulb Is Good
Here’s our step-by-step troubleshooting guide to help you fix the issue of one brake light not working even after replacing the bulb on your car:
Step 1. Check the type of bulb you’re using
The first thing to check is whether you have the correct type, size, and wattage for the replacement bulb for the malfunctioning light.
You can check your owner’s manual to see if the bulb matches the manufacturer’s brake light bulb specifications.
Alternatively, you can compare the bulb with your old one or with the one from the working light.
The bulb you installed could be defective, so you may want to swap it with a working brake light bulb to rule out this possibility.
Step 2. Reinstall the bulb correctly
If the bulb is okay, reinstall it in the socket to see if it works this time. Ensure the bulb sits properly in the socket and is secure, with no loose connections.
If the bulb still does not come on, move to the next step.
Step 3. Inspect the socket
Use an ammeter or test probe to check if there’s power in the socket. If power is present, then the socket connections could be bad, thus causing the light not to come on.
Try wiggling the bulb with the brake pedal on to see if the bulb comes on. If it does, that’s a confirmation of bad contacts.
You can use a flathead screwdriver to help you move out the socket prongs a bit. This will create better contact with your bulb and make it come on whenever you apply the brakes.
You should also check if the socket is corroded. If the contacts look dirty or corroded, clean them and then reinsert the bulb to see if it works.
Here’s a quick video on how to correct a bad contact in your socket:
Video:
Step 4. Examine the wiring
Follow the wiring harness running from the brake light socket for any signs of wear, fraying, cuts, exposed wire, loose connections, etc.
Check the connectors lying at both ends as well as other connectors and splices. If you find any issues with the wires, replace the wiring to see if the problem goes away.
Step 5. Check the ground connection
If the light still won’t work, inspect the brake light assembly ground connection. It should be clean, corrosion-free, and securely connected.
You can try detaching the ground connection and cleaning the connection point. Be sure to reattach it securely for a better ground connection.
If all the above issues check out but the problem persists, you may have no other option but to replace the entire non-working brake light assembly.
NOTE: Sometimes, the electrical diagnosis of your car can prove to be a challenge for most car owners. If you’re not confident in diagnosing your car yourself or you can’t seem to make any progress with your diagnosis, let your mechanic do it for you.
Can You Drive With One Brake Light Not Working?
If one of your brake lights is not working, we don’t recommend driving your car before the light is fixed.
The brake lights play a crucial role in communicating your intentions to slow down or stop to the drivers behind you. This significantly reduces the risk of accidents or collisions.
If you drive with one of your brake lights not working, you risk the following:
- Increased risk of accidents: With only one brake light working, your visibility to drivers behind you about your intention to stop can be greatly affected. Since other motorists are unable to anticipate your braking maneuvers, you’re highly likely to get rear-ended.
- Creating confusion for other drivers: Drivers who see only one brake light working may assume the malfunction light is intentional, leading to confusion and uncertainty. The result is unpredictable driving behavior from the other drivers on the road.
- Traffic rules violation: Most jurisdictions also require you to have the two lower brake lights functioning correctly. If you reside in such a state, then driving with only one brake light will get you pulled over by cops and given a citation or fine for violating this traffic rule.
With this in mind, we recommend taking action to fix the malfunctioning brake light as soon as possible. This will minimize the risk of accidents and enhance your safety on the roads.
Is One Brake Light Not Working Illegal?
In many states, driving with a malfunctioning brake light is illegal and the patrol police will pull over and warn you to fix the malfunctioning brake light.
However, the legality of driving a bad brake light may vary depending on the specific traffic rules in your jurisdiction.
As we’ve just said above, brake lights are a crucial safety feature that helps improve your safety on the roads.
Therefore, you’re highly likely to get stopped by the cops for this issue. However, the consequence of driving with a bad brake light can vary depending on the state you live in.
Be sure to research more about what your local traffic regulations say about driving with one brake light.
If you’re required to have the two lights functioning (and this is pretty much the case in most states), then you should fix your bad brake light ASAP to ensure compliance with traffic laws.
FAQs:
Some potential causes behind one brake light working and the other not working include using a blown bulb, defective socket, using the wrong bulb, or wiring issues. Diagnosing your car will help you find out the exact issue behind this light problem.
A bad fuse is less likely to make one brake light stop working. This is because one fuse usually serves both brake lights in most vehicles. As such, the fuse going bad will affect both lights and not just one.
Conclusion
The issue of one brake light not working but the bulb being good is quite common and affects all types of cars. This article has just highlighted the most common culprits to consider when faced with this issue. These include the wrong type of bulb, an incorrectly installed bulb, a defective socket, wiring issues, or a poor ground connection.
Follow the troubleshooting guide we have outlined in this article to diagnose your car and find the underlying cause behind this light problem. Note that driving with one brake light on isn’t recommended as it can increase the risk of getting rear-ended and even amount to a traffic offense in most states.