Interior lights allow you to get a bright inside view of your car.
However, sometimes the lights may fail, which is not entirely strange, especially for older car models.
Below, we’ve gathered some of the common reasons for failure and what you can do about them.
1. Ensure That Car Doors Are Properly Locked
The dome lights in different cars may have diverse systems and this gets more complicated as technology advances. However, they would still be controlled by the doors in most cars.
Improperly closed doors are the most common mistake regarding dome lights.
So, you may have noticed that your interior lights are connected directly to the doors. Whenever you leave the doors open, they remain ON. The lights can still be ON, even if the doors are only slightly opened or not well jammed.
Hence, you’d want to make sure all your doors are properly closed. Simply reopen and re-close the door or doors that aren’t properly shut and your lights should shut off.
You might see this system as an inconvenience, but it has been an essential safety feature for so long. It reminds you not to drive with your doors unlocked.
The last thing you want is to be the reason for an accident if doors open wide. However, modern safety systems would render the functional door-light precaution obsolete.
In modern vehicles, you can easily detect doors that aren’t properly locked from the driver’s seat.
That also gives specific info and takes away the need to check doors one by one.
Additionally, in some vehicles, the interior lights are also connected to the trunk. This means that the lights would remain ON when the trunk is opened too. Applying the same “reopen and re-close” method to the trunk would ensure it doesn’t fly open while you drive.
2. Use the Dome Light Switch Instead of Relying on Doors
The interior cabin light or dome light comes in handy at night. They have dome-shaped covers and are attached to the ceilings of cars, hence the name.
If automatically programmed, the dome lights would turn ON when any door is opened, reminding you to close it afterward. However, you may not know that the dome light can strictly be controlled manually by the driver or passenger. You can turn it OFF from the switch if you don’t want it ON whenever you open the door.
This is ideal for people who are uncomfortable with the door deciding their illumination.
When you turn it OFF manually, whether or not the doors are locked, it’ll remain OFF. Conversely, when you turn the dome light ON, it remains ON regardless of what you do to the doors. Using the switch instead of relying on doors gives you total control.
This way, it’ll be difficult to have lights that wouldn’t go OFF. That’s because you’d get used to turning it off yourself.
If you’re used to controlling the dome lights manually, they can get stuck. It’s rare, but if it happens, you may need to visit an electrician quickly.
3. Test Your Door Courtesy Switch
You can only access the door courtesy switch or jamb switch when you open your car doors. They are not to be confused with the regular lock and unlock switches in your car.
Instead, the courtesy switch signals the interior lights to come on, and opening your door releases the switch.
As you’ve probably guessed, closing your doors causes them to go off. Your interior lights would remain ON when any one switch is broken or stuck. At this point, it wouldn’t matter if you close your doors properly or not.
Of course, if you manually control your lights, you wouldn’t even notice this problem. Jamb switches are mostly made of plastic, so they’re susceptible to failure.
To diagnose, open your doors and check if any of the courtesy switches are stuck or broken. Just look for any switch that isn’t already in the protruding position. By pushing each and observing the lights, you’d know if there’s a problem.
Usually, you should hear a clicking sound as you push the switch. The clicking sound helps you know if the switch is still healthy. If you don’t hear any sound, it could mean the switch is broken.
When each switch goes in and out as you press and release it, they all work properly.
If any switch is broken, the vehicle would think a door is always open. Consequently, the lights would remain ON. A broken switch should be replaced unless you do not need door-operated lights.
4. Check if the Steering Lever Is Faulty
Many car companies have taken advantage of the advancement in technology to produce outstanding features in their vehicles.
One such improvement is the ability to control the car’s interior lights from the steering lever. This can be done in some modern cars.
A switch may be on the lever attached to the left side of the steering wheel. The lever would control the interior lights, and running lights, with the high- and low-beam headlights.
Since the steering lever can also fail, that might affect operations. So, to prevent such sad stories, it’s best to stick to the regular settings everyone is already used to. It’s less complicated if the dome light is controlled by a switch up there or by doors.
Nonetheless, electricians shouldn’t have much trouble fixing this problem if it should occur.
If you travel at night a lot, make sure to read our article about cars with Xenon headlights.
5. Have a Professional Examine the Wiring
If, after applying the tips above, the problem persists, perhaps it’s time to check the wiring of the lights.
The interior lights of a car are in different categories, including dome lights, map lights, dashboard lights, and so forth. They can all fail simultaneously or separately, depending on the exact wiring system.
While this will usually not be the likely cause of lights not shutting off, we can’t rule it out. It also has a higher likelihood of occurrence in older cars. Still, we’d prefer if this is always your last resort, no matter how old your vehicle is.
You may be able to fix the wiring yourself if you’re tech-savvy with a few tips from an electrician.
If you’d like to try, you’d have to trace the wiring from each door to the frame of the vehicle. There should also be a junction behind the dashboard where the cables come together.
If you discover any physical damage or wear on any of the cables, you’d need to replace them. However, if you’re conflicted, it is best to stick to plan A and visit a professional.
Do My Interior Lights Affect My Battery in Any Way?
The car’s battery can run down if the lights are left ON for a long time. This can be frustrating in the morning when you need to go out quickly.
For batteries that are already weak, the interior lights would have devastating effects on them if left ON overnight. So you must ensure that you never leave your interior lights on for hours at a time.
Ultimately, it’s better to disconnect your battery terminals if you can’t establish a way to turn the lights off. This ensures your battery would live to fight another day.
Make sure to also read our article about why a car’s lights won’t stop blinking.
Beyond the inconvenience this problem may cause, other severe outcomes are possible. Lights that won’t shut off would negatively impact overall performance after affecting the car battery.
Also, a weak battery would cause your headlights to become dim and this would affect night movements.
What’s more, when slow engine cranking occurs, it’s usually a bad sign showing that your battery is disturbingly weak.
Finally, it shouldn’t cost too much to repair a malfunctioning dome light. So, if it malfunctions, take advantage of the affordable repair cost and have it checked immediately.
Please also read our article about car door drains, especially if your car smells moldy.
How to Replace a Courtesy Light Switch in Most Cars | Your Mechanic
Interior Car Lights Won’t Turn Off – Causes And Fixes | Mechanic Base