1. Lighting and Wiring Fundamentals
Chapter 32

2. Objectives Describe differences between wire and cable
Explain the fundamentals of operation of automotive lighting and wiring
List when different circuit protection devices would be used

3. Introduction Lights and wiring: Electricity is provided through:
Can be a complicated system
Electricity is provided through:
Wiring
Cables
Fibers
Circuit protection devices:
Fuses
Circuit breakers
Fusible links

4. Wire and Cable Chemicals, corrosion, vibration, and heat
Damage wiring
Primary and secondary wires
Primary wiring: low-voltage wiring
Secondary wiring: ignition wiring
American Wire Gauge (AWG): describes the size of wire or cable used
Cables: large wires that allow more electrical current to flow

5. Circuit Protection Devices
Fuse: protective device designed to melt when the flow of current becomes to high
Replaceable fuses
Blade type
Ceramic type
Glass tube cartridge type
Fuse link
Length of wire smaller in diameter than the wire it is connected to

7. Circuit Protection Devices (cont'd.)
Circuit breakers
Used in automobiles: usually self-resetting
Breaker “trips” and then resets
Bimetal strip: two metal strips with different expansion rates
Higher expansion metal will become longer and will break the switch contact
Contact is reestablished when it cools

8. Lighting Light bulbs Often called lamps
Electricity flows through filaments
Filament provides a resistance to electron flow
It heats up and glows, causing light

9. Headlamps Headlight and headlamp Sealed-beam headlamp construction
Terms are used interchangeably
Intensity of a headlamp: rated in candlepower
Sealed-beam headlamp construction
Have an inner glass or plastic reflector surface
Type I lamp: high beam only
Type II lamp: both low and high beams
Halogen lamps
Produce a 25% higher output of “whiter” light
Conventional sealed beam or composite

11. Headlamps (cont'd.) High-intensity discharge lamps Adaptive headlights
Provide three times more light than conventional halogen headlamps
Adaptive headlights
Can swivel up to 15 degrees right or left
Headlight switch
Multifunction on steering column or mounted on dash panel
Typically two or three positions besides the off position

13. Headlamps (cont'd.) Dimmer switch Automatic headlight dimmer
Changes headlights from low to high beam
Automatic headlight dimmer
Detects oncoming cars
Courtesy lights
Interior dome and underdash lights
Headlight wiring
Many use grounded electrical systems
Daytime running lights: powered when engine is running

14. Headlamps (cont'd.) Automatic headlights Flash to pass
Use a light-sensitive photocell sensor
Delay shutoff keeps lights on for a short period
Flash to pass
Raising turn signal activates high beams
Driving lights and fog lamps
Occasionally installed as original equipment
Normal lights do not work well in fog
Fog reflects light back at the driver

15. Taillights Taillight bulbs Newer vehicles Come in many sizes and types
Are usually ground through the base to the bulb socket
Light socket: usually grounded to frame
Newer vehicles
Bulbs have a plastic socket mounted in plastic housings

16. Light Bulb Identification
Miniature lights: bulbs smaller than headlamps
Correct replacement bulb must be used
Otherwise, circuit problems could result
Bulbs are numbered by the ANSI
Identification number is the bulb trade number
Stoplight switch
Activated by a mechanical switch on brake pedal
Taillights and brake lights
Taillight bulbs have one or two filaments
Activated by brakes

18. Fiber Optics
Light can be transmitted through a special plastic called polymethacrylate
Fiber-optic strands illuminate indicator on fender
LED and neon lights
Energy efficient, long lasting, and compact
Center high-mount stop lamps
Row of LEDs, filament bulb, or a neon tube
Adaptive brake lights
Intensity increases as driver pushes on brake pedal

19. Turn Signals Turn signal circuit components Turn signal Switch
Signal flasher
Two indicator bulbs
Stoplight filaments or rear stoplight bulbs
Two bulbs in the front of the vehicle
Turn signal
Usually part of a multifunction switch in the steering column

20. Signal Flasher Operation
Turn signal flashers
Turn signals and safety hazards
Mechanical or automatic
Electronic turn signal flashers
Operate when a transistor is triggered on and off
Transistor: electronic switch with no moving parts
Operate turn signals and hazard warning lights
Relay turn signals
Mechanical
Electronic

22. Hazard Flashers Required on cars manufactured after 1967
Circuit is powered directly from the battery
Emergency flasher switch locations
Side of the steering column
Dash panel
Glove box
Emergency warning systems
Use a variable load flasher

23. Back-Up Lights Operation
Key is on
Transmission selector is moved to R position
Lights at the rear of the vehicle are illuminated
Provide a white light that allows a driver to see
Provides a warning to other drivers
Some vehicles use the same fuse for turn signals and back-up lights
Current is supplied from the fuse panel to the back-up light switch

24. Wipers and Horn Windshield wiper motor Intermittent wipers
Wiper circuit has fuse or circuit breaker and wiper switch
Electromagnetic wiper motors: two brushes on armature
Typical permanent magnet motor: three brushes
Intermittent wipers
Allow variations in the time interval
Rain-sensing: begin automatically when water sensed
Speed-sensitive: controlled with sensor input

26. Wipers and Horn (cont'd.)
Windshield washer
Components
Reservoir
Switch and pump
Washer nozzles
Hoses and connections
Types and features
Rear window wiper-washer
Headlight wiper-washers
Windshield washer low-fluid indicator

27. Wipers and Horn (cont'd.)
Horn circuit components
Horn
Fuse and wiring
Horn switch
Relay
Dashboard is called an instrument panel
Combined analog and digital displays
Electric gauges
Thermal/bimetal gauges, magnetic gauges, and digital panel gauges

29. Miscellaneous Gauges Several gauges are on the instrument panel
Speedometer/odometer
Tachometer
Engine coolant temperature gauge
Engine oil pressure gauge
Fuel level gauge
Lamp-out warning light
Other warning lights
Other electrical accessories