Courtesy lighting

What is courtesy lighting?

Courtesy lighting is a comfort and safety feature found in almost all modern vehicles. It consists of a set of lights that turn on automatically to welcome the driver and passengers. This lighting typically activates when unlocking the doors remotely, when opening a door, or turns off with a time delay after the doors are closed or the engine is started. Much more than a simple gadget, it plays an essential role in the user experience, especially at night or in dark locations such as underground parking lots.

The different types of courtesy lighting

What used to be a simple central dome light has evolved into a complex and sophisticated system comprising several elements working in tandem:

• The dome light: The central element, located in the front and often in the rear, providing the main illumination for the cabin.
• The reading lights: Individual auxiliary lamps allowing passengers to read without disturbing the driver.
• Footwell lighting: Located at foot level, it facilitates entry into and exit from the vehicle and helps retrieve items dropped on the floor.
• Puddle lights: Integrated beneath the exterior rearview mirrors, they project a light beam onto the ground to illuminate the entry area and avoid stepping into a puddle or onto an obstacle. Some premium manufacturers even project the brand logo.
• Door sill illumination: Often bearing the model or trim name, it lights up when the door is opened to highlight the threshold and guide your footing.
• Glove box and trunk lighting: Essential for easily finding what you are looking for in these storage areas.
• Illuminated vanity mirrors: Integrated into the sun visors, they activate when the mirror cover is opened.

Operation and technological evolution

The courtesy lighting system is managed by the vehicle's onboard computer (Body Control Module - BCM). It receives information from the door sensors, the central locking system, and the immobilizer to activate at the right time. The time delay, which keeps the lights on for a few seconds after the doors are closed (fade-out effect), allows occupants to fasten their seatbelts or locate the ignition switch comfortably.

The advent of LED (Light Emitting Diode) technology has revolutionized courtesy lighting. Compared to traditional incandescent bulbs, LEDs offer a significantly longer lifespan, very low energy consumption, and a brighter, whiter light. Their small size has also allowed designers to integrate them into previously inaccessible locations, such as the interior and exterior door handles or as thin light strips.

A close link with ambient lighting

It is important not to confuse courtesy lighting with ambient lighting, even though the two are often connected. Courtesy lighting is functional and temporary, designed for welcoming occupants. Ambient lighting, on the other hand, is decorative lighting that remains active while driving to create a specific atmosphere in the cabin. On many modern vehicles, courtesy lighting turns on at high intensity upon opening, then dims to blend into the color and intensity of the ambient lighting once the doors are closed and the engine is running, ensuring a smooth and harmonious transition.

In conclusion, courtesy lighting is one of those features that you only really notice when it's missing. From a purely utilitarian feature, it has become a key element of comfort, perceived safety, and a vehicle's premium identity, transforming every entry into the vehicle into a pleasant and reassuring experience.