Most people associate courtesy lamp with the dome lights in car cabins. But they are more than these ceiling lamps.
Regardless of the location, these lights turn on when you open something, usually the car door.
Here’s all you need to know about these lights, including the symptoms and causes of their failure.
What Is a Courtesy Lamp?
A courtesy lamp is a switched interior automobile light that automatically turns on when you open something, such as the door.
The typical ones are dome and puddle lights.
While these lights turn on automatically when you open something, some have switches for manual control.
You can set them to remain off when you open the door or turn them on after closing the doors.
Types of Courtesy Lamps
Most vehicles have these courtesy lights.
Center-roof-mounted dome lights illuminate the interior cabin space and have a door switch for automatic activation/deactivation when you open or close the door. Some vehicles activate this courtesy lamp when you turn off the ignition.
Puddle lights also turn on when you open the door. Depending on the vehicle, they can be under the side-view mirror or the door.
But both illuminate the area around the car door to prevent you from stepping on a puddle when entering the vehicle.
A car door open with the puddle and footwell lights on
If this light is under the side mirror, it is external, which falls outside the boundaries of the courtesy lamp’s definition.
But since it falls in the same category as the one under the door inside the vehicle, we’ll label it as an exception.
These tiny, sometimes movable lights help you read maps when navigating during night driving.
They are handy in areas with no GPS coverage. Like dome lights, reading lamps are roof-mounted, and most people often use the two together to enhance visibility.
An LED reading light
Accent lights are purely for aesthetics because they make the vehicle appear classy. And they can change the light color to suit your mood.
As the name suggests, these lights illuminate the driver and front passenger’s foot area.
Although they help with nighttime vehicle entry and exit, they mostly enhance the vehicle’s appearance because you can’t miss your steps.
These lights illuminate the trunk when loading, unloading, or locating objects in the space at night.
An LED trunk light
Sun Visor Lights
Sun visors with vanity mirrors usually have lights around the reflective surface to let you see yourself and polish up before exiting.
The Sun visor lights
How Courtesy Lights Work
We’ll focus on the dome lights because they are the primary courtesy lamps. These lights have a straightforward operating mechanism.
They are part of an electrical circuit where the switch is on the door, and they are the load.
A headliner with multiple courtesy lights
When you open the door, the switch contacts touch each other, closing the circuit to activate the lights.
However, modern vehicles have computer modules to simplify and minimize the electrical wiring.
Therefore, the switch sends the activation signal to the BCM (Body Control Module), which turns on the dome courtesy light.
This lamp circuit usually has a secondary switch mounted right next to it with three settings: on, off, and door.
The first two settings give you manual control over the lamp’s activation, but the last setting lets the door switch turn the bulb on and off.
A dome courtesy light with three settings
Symptoms of Failing or Faulty Courtesy Lamps
Like other car parts, courtesy lamps will wear out at some point or experience malfunctions.
The typical symptoms of these failures or malfunctions include the following.
Lamps Fail To Turn On
If the lamp does not turn on when you open the door, the point of failure could be either of these components.
- Burnt-out bulb
- Blown fuse
- Wiring issue
- Damaged switch
- BCM issue (if modern)
In most cases, you only have to replace the bulb to restore the lamp.
Bulbs Stay On After Closing the Door
If the light stays on after closing the door, the issue is not a burnt-out bulb. You have to troubleshoot the problem further to determine its source.
An open car door with the puddle light on
For instance, you can turn the manual switch off and see if it remains on. If the bulb glows, you might have a faulty BCM, wiring, switch, or relay.
This issue requires immediate fixing because it can drain and damage your battery, especially if your vehicle lacks a battery-saving function.
But if the bulb turns off, repair or replace the door switch.
Blinking or Dim Lights
Dim or blinking lights often occur due to weak batteries, wiring issues, or switch faults.
The switch can get stuck, leaving a thin path between the contacts, which can cause arcing.
How to Replace Your Courtesy Lamps?
You’ll only need a screwdriver to replace this bulb. Find the notch in the plastic cover and insert the screwdriver to pop it out.
Remove the burnt-out bulb and insert the new one. Check whether it turns on by opening the door or manually flipping the switch.
Replacing the fuse is even simpler, but you have to identify the correct courtesy lamp fuse in the fuse box.
Check the owner’s manual or electrical diagram to find it, remove it using a fuse puller, and then fit in the new one.
Cost of Replacing Courtesy Lights
Modern vehicles feature energy-efficient LED courtesy lamps that have a long lifespan.
If this component wears out, you can get a replacement for around $10-$80. This cost includes labor.
A dome light costs about $5-$10, while labor costs around $60.
Replacing this bulb is simple, and you can do this DIY task to avoid paying the high labor costs. You’ll only need a screwdriver.
In a nutshell, courtesy lamps are convenience lights that provide task, accent, or ambient lighting.
Modern cars have more of them than older ones and with more switches due to the BCM control.
If either light fails to work, use the diagnosis above to identify and fix the issue. That’s it for now.
Contact us if you need wires to wire these LED bulbs or other vehicle wiring solutions.