Twilight Sentinel is a device on
General Motors
The General Motors Company (GM) is an American Multinational corporation, multinational Automotive industry, automotive manufacturing company headquartered in Detroit, Michigan, United States. It is the largest automaker in the United States and ...
cars that senses outside light and turns the exterior lights on and off depending on lighting conditions.
In addition, Twilight Sentinel also allows the driver to set a timer (located with the headlight switch) that delays shutting off the headlights for a specified time period, usually up to three minutes. The driver can park the vehicle, shut off the car's engine and exit the automobile after dark, then use the headlights to light the path into a nearby building, such as a house, before the system shuts the headlights off automatically.
An electric photocell located in the dashboard detects the environmental lighting conditions and activates the headlights as needed. Usually, this means turning on the headlights at dusk and shutting them off after sunrise. The system requires that a change in the environmental lighting conditions remains consistent for approximately 10 seconds before a change in the headlights is activated. For example, during daylight hours, the headlights would not turn on due to the momentary darkness of driving under a bridge or through a short tunnel.
Twilight Sentinel can be disabled by switching off the feature or by manually turning on the headlights and earlier versions did not turn on the exterior lights for driving conditions such as heavy rain or fog, while later improvements to the system linked to GM's
RainSense
A rain sensor or ''rain switch'' is a switching device activated
by rainfall. There are two main applications for rain sensors. The first is a water conservation device connected to an automatic irrigation system that causes the system to shut do ...
automatic windshield wiper system to turn lights on automatically when the wipers are on.
Twilight Sentinel was first offered exclusively on the 1964 Cadillac lineup but was expanded to other divisions later.
A related feature offered on many General Motors models during the 1950s and 1960s was the
Autronic Eye headlight dimming system. Cadillac later referred to its automatic dimming system as "Guidematic Headlamp Control" which encompassed Twilight Sentinel and Dimming Sentinel controls.
Ford Motor Company
Ford Motor Company (commonly known as Ford) is an American multinational automobile manufacturer headquartered in Dearborn, Michigan, United States. It was founded by Henry Ford and incorporated on June 16, 1903. The company sells automobi ...
offers a nearly identical exterior lights on/off/delay shut-off system called "AutoLamp". The Ford automatic headlamp system could be had with automatic dimming on
Lincoln
Lincoln most commonly refers to:
* Abraham Lincoln (1809–1865), the sixteenth president of the United States
* Lincoln, England, cathedral city and county town of Lincolnshire, England
* Lincoln, Nebraska, the capital of Nebraska, U.S.
* Lincol ...
models.
Chrysler
Stellantis North America (officially FCA US and formerly Chrysler ()) is one of the " Big Three" automobile manufacturers in the United States, headquartered in Auburn Hills, Michigan. It is the American subsidiary of the multinational automoti ...
offered Twilight Sentinel on the
Imperial
Imperial is that which relates to an empire, emperor, or imperialism.
Imperial or The Imperial may also refer to:
Places
United States
* Imperial, California
* Imperial, Missouri
* Imperial, Nebraska
* Imperial, Pennsylvania
* Imperial, Texa ...
from 1967 to 1975; other full-size C-body Chrysler products from the mid-sixties to the mid-seventies had it as an option as well.{{cn, date=April 2020
Automotive technology tradenames
General Motors