Instructor Name Your Name 9 CHAPTER Learning Objectives List the various lights used on a truck and indicate the location and color Describe why an incandescent light draws more current when first switched on then when the lamp is illuminated at full brilliance ID: 304196
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Slide1
Lighting Systems
Instructor Name: (Your Name)
9
CHAPTERSlide2
Learning Objectives
List the various lights used on a truck and indicate the location and colorDescribe why an incandescent light draws more current when first switched on then when the lamp is illuminated at full brillianceExplain how the various types of turn signal flashers operateDescribe the difference between separate stop/turn lamps and combination stop/turn lampsSlide3
Learning Objectives (continued)
Troubleshoot a rear lighting problem on a truck with combination stop/turn lampsTroubleshoot a trailer lighting problemList the advantages and disadvantages of LED lightingSlide4
Exterior Lighting Requirements
FMVSS 108 sets the standards for all exterior lightingMarker Lamps – Located on the sides of a truck or trailerIdentification Lamps – Three centered on cab and rear of box or trailer. Identification light are sometimes referred to as three bar light.Clearance Lights – Located on front a rear top most corners of vehicleSlide5
Exterior Lighting Requirements (continued)
Tail Light – Located on the rear of the truck or trailerParking Lamps – Located the front of the truckLicense Lamp– Located above the rear license plateSlide6
Figure 9-3
Truck and trailer lighting locations.Exterior Lighting RequirementsSlide7
Incandescent Lamp Ratings
Design Voltage – The rating by which all other lamp characteristics are measuredCandlepower – Indicate the brightness of the lampAmperage Rating – Indicates the approximate current draw at the rated voltagePower Rating – Listed in watts, it is the amount of heat the lamp will dissipateSlide8
Bayonet Type Lamp Base
Figure 9-5 Bayonets on lamp base used to retain lamp in socket and provide ground connection.Slide9
Dual Filament Bayonet Type Lamp
Figure 9-7 Dual-filament lamp; two filaments share a common ground.Slide10
Wedge-Type Lamp Base
Figure 9-6 Wedge-type lamp base.Slide11
Head Lamp Lens
Figure 9-9 Headlamp lens.Slide12
Halogen Sealed Beam Lamp
Figure 9-10 Halogen sealed beam.Slide13
Head Light Reflector Directs the Light
Figure 9-11 Headlamp reflector directs the light.Slide14
Halogen Lamp
Figure 9-12 Halogen lamp.Slide15
Composite Headlamp with Interchangeable Halogen Lamp
Figure 9-13 Composite headlamp with replaceable halogen lamp.Slide16
Handling Halogen Lamp
Figure 9-14 Handling a halogen lamp.Slide17
High Intensity Discharge (HID) Lamp
Figure 9-15 Xenon headlamp components.Slide18
WARNING
Never add any extra electrical loads to the headlight circuit, such as driving light. The extra current may lead to headlight circuit failure.Slide19
Headlamp Switch in the Park Position
Figure 9-17 Headlamp switch in the part position.Slide20
Headlamp Switch in the On Position
Figure 9-18 Headlamp switch in the headlamp ON position.Slide21
Floor Mounted Dimmer Switch
Figure 9-19 Floor-mounted dimmer switch.Slide22
Flashers
Wired in series with turn signal lampsHeater element heats when current flows heating the bimetallic strip causing it to bendBimetallic strip bends opening the circuit in the flasher stopping current flow to lampsWhen current flow stops, heater and bimetallic strip cools closing switch contacts and lighting lampsThis process repeats itself up to 70 to 110 per minute Slide23
Thermal-Type Flasher
Figure 9-20 Thermal-type flasher.Slide24
Stop Light Switch
Stop or brake lamps are located at rear of truckTrucks with air brakes and no tractor protection valve usually have primary and secondary circuit air pressure stop lamp switchesAir pressure activated stop lamp switches are normally open and close at approximately 2 to 6 psi (14 to 41 kPa)Trucks with tractor protection usually only have one stop lamp switch located at trailer brake air supply circuitSlide25
Tech Tip
It is important to note that left and right sides of vehicle always refers to the operators left and right when seated in the drivers seat. This is opposite of left and right when viewed facing the front of the truck. Slide26
Turn, Signal, and Stop LampsCombination Stop/Turn
– Rear turn signals, hazard lights, and stop lamps all use one single lamp on each sideSeparate Stop/Turn – Amber turn signal lamps that are separate, red stop lamps that are separateSlide27
Turn Signal With Stop Light Switch Open and No-Turn Position
Figure 9-22 Turn signal with stop lamp switch open and no-turn position (off).Slide28
Stop Lamp Switch Closed, Turn Signal Switch Off
Figure 9-23 Stop lamp switch closed, turn signal switch off, both rear combination lamps illuminate.Slide29
Turn Signal Switch in the Left Turn Position
Figure 9-24 Turn signal switch in the left turn position.Slide30
Left Turn and Stop Lamp Switch
Figure 9-25 Left turn and stop lamp circuit.Slide31
Dual Filament Bulbs and Head Light Switch in Stop Turn Light Circuit
Figure 9-26 Adding headlamp switch and dual-filament lamps to simple turn signal switch.Slide32
Open Ground Creates a Series Resistor of Dual Filament Lamp
Figure 9-27 Filaments are in series when dual-filament lamp ground circuit is open.Slide33
Current Path for Left Rear Park Light Through the Elements of the Dual Filament Lamps
Figure 9-28 Path for current flow through left rear lamp stop/turn filament to right rear stop/turn filament with left rear ground open and park lamps on.Slide34
Open Ground in Left Hand Rear Combination Lamp Circuit
Figure 9-29 Left rear combination lamp ground open. Park lamps are on, stop lamps are on, and neither left rear filament is illuminated.Slide35
Current Path for Left Rear Brake Light Through the Elements of the Dual Filament Lamps
Figure 9-30 Left rear combination lamp ground is open. Park lamps are off, stop lamps are on, and all running lights illuminate dimly when stop switch is closed.Slide36
SAE J560 Trailer Plug
Figure 9-33 SAE J560 trailer electrical receptacle and plug.Slide37
SAE J560 Wiring Standards
Figure 9-34 Trailer standard wire insulation colors.Slide38
Trailer Socket Connections
Figure 9-36 Trailer socket and trailer cord connector layout looking into the mating ends of the connectors.Slide39
Advantages of LEDs
Longer life expectancy, up to 100,000 hoursLess heat generatedLess susceptible to shock damageFast turn on timeAlmost no surge current Maintain brightness over life of bulb Slide40
Disadvantage of LEDs
Higher initial cost Prone to theftMay be necessary to scrape snow and ice from lamps in winter driving conditions due to the fact less heat is generatedSlide41
LED Construction
Figure 9-40 LED construction; a series resistance is necessary to limit current flow through the LED.Slide42
Tech Tip
Luggage compartment lamps are often overlooked in the search of parasitic key-off load currents because there are no windows in the luggage compartment to determine if the luggage lamps are shutting off when the luggage doors are closed.Slide43
Instrument Panel Illumination
Figure 9-42 Instrument panel illumination.Slide44
Summary
Truck lighting is subject to FMVSS 108 and CMVSS 108 and other government requirements. It is important to perform lighting repairs so that the truck does not violate the various lighting requirements.Incandescent lamps are lamps that contain a thin piece of wire such as tungsten. The sealed glass container does not contain oxygen, which permits the element to glow white hot (incandesce) without being consumed.Slide45
Summary (continued)
Dual filament lamps contain two filaments in one lamp globe. The two filaments share a common ground but have separate voltage sources for each filament. Dual filament lamps are commonly used for turn signals and tail lamps, permitting one lamp to perform two or more functions.Slide46
Summary (continued)
The resistance of an incandescent lamp increases significantly as the element is heated due to current flow. This causes a surge current to flow when the lamp is first illuminated. The surge current of a typical incandescent lamp may be 10 times or more than the current draw with the lamp at operating temperature.Slide47
Summary (continued)
Trucks and trailers may have combination stop/turn lamps or separate stop/turn lamps.Trucks with combination stop/turn lamps can exhibit some seemly strange behavior when a ground for a dual filament lamp is open. Other failures such as filaments that are shorted together can also cause problems that seem to be difficult to diagnose.Slide48
Summary (continued)
Trailers receive voltage for lighting from the tractor through a seven way trailer socket. This socket is standardized in North America and other parts of the world.Trailer sockets that are green and marked with the abbreviation ABS indicates that the center pin circuit is powered anytime the truck ignition is active. This center pin is used to supply the trailer ABS control module. LED lighting has several advantage over incandescent lights, such as long life. Disadvantages of LED lighting include high initial cost.