Car interior lights can be broken into different categories such as dashboard lights, dome lights, map lights, and others, and they can fail at the same time or one at a time. Since there are many different types of car lights, a malfunction can either be an annoyance or a real safety issue. In any case, figuring out what to do when your car’s interior lights stop working is usually a pretty simple diagnostic process that can be done with some help. basic tools such as screwdrivers and a test light .
What is car interior lighting?
Interior lighting is one of two fairly wide umbrellas that cover all kinds of lighting in and around your vehicle. The other category is outdoor lighting, which covers everything from your headlights to the taillights and everything in between.
The interior lighting of the car can be further divided according to its intended purpose. Dome lights are usually located overhead and illuminate the interior of your car at night, whereas map lights, located on or near sun visors, were originally intended to literally lighten the reading physical cards (links to PDF) at night. Dashboard illumination can help you see your tools such as the speedometer, at night and often adjusted to prevent night blindness.
Some cars have other specialized categories of interior lighting, such as step lights that help you get into your car at night without tripping, and some even have «welcome floor mats» that project a logo or a simple puddle of light onto the ground when you open it. Door.
Depending on the vehicle, all interior lighting may be on a single circuit, or there may be multiple circuits. A single indoor light can also be controlled by multiple switches, so there are a number of different possible ways for them to fail. For example, a dome light may have a manual switch in the light, even if it can also be turned on and off or off by a switch on the dashboard.
Start with a dome light or dimmer
When your car’s interior lighting stops working, the best place to start is also the easiest solution. The most common cause of this problem is when someone other than the driver is using the dome light or dimmer. This can leave the interior lights in a state where they no longer turn on when you open the door.
Depending on how your interior lights are wired and the types of switches, you may need to press a different button combination to turn on the interior lights. In general, you’ll want to try turning the dimmer (if it has one) and try it in different positions. In some cases, turning the dimmer all the way in one direction will cause it to click, which may indicate that it is either on or off.
With the dimmer in different positions, or the built-in dash light switch in different positions, you can try controlling your dome lights, map lights, or other interior lights with their separate switches.
If you can’t turn on the interior lights by trying various dimmer or dome switch combinations, then you’re likely to run into a real problem somewhere along the line.
Blown fuses and car interior lights
When all of your car’s interior lights stop working at the same time, but other things such as radio are still working this is a good hint that the root cause is what unites all the lights. In most cases this there will be a fuse so that’s the next thing to check.
Depending on how your vehicle is configured, the fuse box may be located in or near the glove box, under the dash, or in the engine compartment. Some cars even have more than one fuse box, so your owner’s manual can be very helpful in finding the right one. Otherwise, you can usually search the internet to find a picture of your exact fuse box.
The fuse you are looking for is usually the «lights» fuse, although this may vary depending on the vehicle. The only way to know for sure is to find a wiring diagram for the specific make, model, and year of your car, but it’s usually sufficient to check all fuses labeled «headlights» or similar.
Report if a fuse is blown
While you can usually tell if a fuse is blown by looking at it, this is not always the case. Fuses can blow and still look good, so the only way to test them is to use a tool like a multimeter or test light. If you have a multimeter and you can’t find continuity between the fuse terminals, it means the fuse is blown.
The easiest way to check fuses is with a test light. All you have to do is press one end against bare metal somewhere on your machine and then touch the end of the probe on each side of the fuse. With the ignition key in the on position, your test light should be on when you touch both sides of each fuse.
If your test light stays dark on one side of the fuse, it means the fuse is blown and you should replace it with the exact same type of fuse. Never use a fuse with a large amount, as this can cause catastrophic damage to the wiring in your car.
Wiring issues, shorts and interior lighting
While it is technically possible for a fuse to blow without another underlying problem, this is not very common. In most cases, a blown internal light fuse means there is some sort of short circuit in the system. It could be a permanent failure or a temporary failure, but the only way to know for sure is to replace the fuse and see what happens.
If you replace a blown internal fuse and it blows again, you have dealing with a short circuit . It can still be something you can handle yourself, but some shorts will require the attention of a professional technician.
Most shorts can be traced to the places where the wires are usually bent and crimped, so this is the best place to start. If your vehicle has indicator lights on the sun visors or lights located on the doors, it’s usually best to find a short in one of these circuits.
If you check all the wires they go through to your doors or sun visors and can’t find a short, then your best bet is to call a professional.
Bad door switches and interior lighting
The final point of failure that can affect all of your indoor lights at the same time is a bad door switch. These switches can be found in the door jambs of most vehicles, which is why they are often referred to as door switches.
When the interior lights in a car are working properly, they usually turn on when you open the door and then turn off some time after you close the door. This process is based on a switch in the door jamb that opens when the door is opened and closes when the door is closed.
These switches are often covered with a rubber boot that can be removed with a flat blade screwdriver. The switch can then be unscrewed or unscrewed. If you have a multimeter, you can test the switch by connecting to both terminals and checking for continuity. Then you can activate the switch and check again. If the readings do not change, then the switch is bad.
Interior lighting modules
If your interior lights stayed on for a while after closing the doors, there might be some kind of timer module in the circuit. So if your fuses are good, door jamb switch OK and everything else works fine you may be facing a more difficult problem.
While replacing this type of component is usually not that difficult, throwing away parts when solving a problem is rarely the best or most effective solution. With this in mind, a professional technician will be able to help you if you get this far without finding any obvious problems.