AUTOMOTIVE LIGHTING
SYSTEMS
Question # 1
How many light bulbs are on a modern
vehicle?
 Taillights – 8
 Front – 6
 Side - 4
 Interior – 15
 IP & Controls – 22 – 24
 Total - 56

Lamps
Double and single tungsten filaments
 Filament is in a vacuum

Lamp Ratings
Trade
Name
Design
Voltage
Design
Amperage
Wattage
Types of Headlights
Sealed Beam – Used between 1939 – 1975
 Halogen – Bulb filled with halogen, Burns
hotter, lasts longer
 Composite – fixed housing with replaceable
bulb
 HID – High Intensity Discharge – Light
emitted by a spark

HID
Brighter
 Wider & deeper field
of vision
 Use 37% less power
 Last up to 100,00
miles


* As compared to
Halogen bulbs
HID
Separate Ballast –
produces 80v
 Ark tube (bulb) –filled
with Xenon gas
 Electrons excite salts in
Xenon gas creating the
ark which produces
light

Headlight Switches
Controls driving, parking and IP
illumination (dimming)
 Locations – On dash or steering column
 Separate switch for high beam activation

Low Beam Circuit
High Beam Circuit
Exterior Lighting

Taillights – Contain parking, brake, turn
signals, backup, license plate lights
Can be housed in one unit or in several units
 Incandescence bulbs or LED
 Separate 3rd brake light asm. - CHMSL

Side Markers – Part of parking lights circuit,
makes vehicle visible from the side
 Fog Lights – Can be clear or yellow, factory or
aftermarket, controlled by separate switch

Interior Lighting
Courtesy Lights – Trunk, glove box, under
hood, roof & floor lighting
 Ip & Panel Lighting – Illuminate gauges
and controls with dimmable lighting
