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Lighting and Wiring Fundamentals

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Presentation on theme: "Lighting and Wiring Fundamentals"— Presentation transcript:

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


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