Headlight Switch

Step by step guide on how an automotive headlight control switch works, this information pertains to most cars.

Step 1 - Headlight operation controls are performed by a manually controlled switch or by photosensitive sensors located near the dashboard. These controls allow the driver or the body computer to operate the headlights in various conditions.

Headlight Control Switch

Step 2 - The first position on a headlight switch is the running light illumination, this position is used to power up the running light system only.

Running Lights

Step 3 - These running lights are used when visibility is low such as at dusk, or when fog has covered the road.

Running Lights

Step 4 - The main control for the headlight switch is the headlights themselves, in this position the headlight will remain "ON" until the ignition switch is turned off, or the switch is removed from this position.

Headlight Setting

Step 5 - Headlights are used at night, to help the driver observe the road in low visibility conditions.

Headlight Operation


Written by
Co-Founder and CEO of
35 years in the automotive repair field, ASE Master Technician, Advanced Electrical and Mechanical Theory.


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Article first published (Updated 2015-01-09)