1. LIGHTING AND SIGNALING CIRCUITS56
LIGHTING AND SIGNALING CIRCUITS
LIGHTING AND SIGNALING CIRCUITS

2. Figure Dual-filament (double-contact) bulbs contain both a low-intensity filament for taillights or parking lights and a high-intensity filament for brake lights and turn signals. Bulbs come in a variety of shapes and sizes. The numbers shown are the trade numbers.
Figure Dual-filament (double-contact) bulbs contain both a low-intensity filament for taillights or parking lights and a high-intensity filament for brake lights and turn signals. Bulbs come in a variety of shapes and sizes. The numbers shown are the trade numbers.

3. Figure Bulbs that have the same trade number have the same operating voltage and wattage. The NA means that the bulb uses a natural amber glass ampoule with clear turn signal lenses.
Figure Bulbs that have the same trade number have the same operating voltage and wattage. The NA means that the bulb uses a natural amber glass ampoule with clear turn signal lenses.

4. Chart Bulbs that have the same trade number have the same operating voltage and wattage. The NA means that the bulb uses a natural amber glass ampoule with clear turn signal lenses.
Chart Bulbs that have the same trade number have the same operating voltage and wattage. The NA means that the bulb uses a natural amber glass ampoule with clear turn signal lenses.

5. Chart 56-1 (continued) Bulbs that have the same trade number have the same operating voltage and wattage. The NA means that the bulb uses a natural amber glass ampoule with clear turn signal lenses.
Chart 56-1 (continued) Bulbs that have the same trade number have the same operating voltage and wattage. The NA means that the bulb uses a natural amber glass ampoule with clear turn signal lenses.

6. Chart 56-1 (continued) Bulbs that have the same trade number have the same operating voltage and wattage. The NA means that the bulb uses a natural amber glass ampoule with clear turn signal lenses.
Chart 56-1 (continued) Bulbs that have the same trade number have the same operating voltage and wattage. The NA means that the bulb uses a natural amber glass ampoule with clear turn signal lenses.

7. Chart 56-1 (continued) Bulbs that have the same trade number have the same operating voltage and wattage. The NA means that the bulb uses a natural amber glass ampoule with clear turn signal lenses.
Chart 56-1 (continued) Bulbs that have the same trade number have the same operating voltage and wattage. The NA means that the bulb uses a natural amber glass ampoule with clear turn signal lenses.

8. Chart 56-1 (continued) Bulbs that have the same trade number have the same operating voltage and wattage. The NA means that the bulb uses a natural amber glass ampoule with clear turn signal lenses.
Chart 56-1 (continued) Bulbs that have the same trade number have the same operating voltage and wattage. The NA means that the bulb uses a natural amber glass ampoule with clear turn signal lenses.

9. Chart 56-1 (continued) Bulbs that have the same trade number have the same operating voltage and wattage. The NA means that the bulb uses a natural amber glass ampoule with clear turn signal lenses.
Chart 56-1 (continued) Bulbs that have the same trade number have the same operating voltage and wattage. The NA means that the bulb uses a natural amber glass ampoule with clear turn signal lenses.

10. Chart 56-1 (continued) Bulbs that have the same trade number have the same operating voltage and wattage. The NA means that the bulb uses a natural amber glass ampoule with clear turn signal lenses.
Chart 56-1 (continued) Bulbs that have the same trade number have the same operating voltage and wattage. The NA means that the bulb uses a natural amber glass ampoule with clear turn signal lenses.

11. Chart 56-1 (continued) Bulbs that have the same trade number have the same operating voltage and wattage. The NA means that the bulb uses a natural amber glass ampoule with clear turn signal lenses.
Chart 56-1 (continued) Bulbs that have the same trade number have the same operating voltage and wattage. The NA means that the bulb uses a natural amber glass ampoule with clear turn signal lenses.

12. Chart 56-1 (continued) Bulbs that have the same trade number have the same operating voltage and wattage. The NA means that the bulb uses a natural amber glass ampoule with clear turn signal lenses.
Chart 56-1 (continued) Bulbs that have the same trade number have the same operating voltage and wattage. The NA means that the bulb uses a natural amber glass ampoule with clear turn signal lenses.

13. Chart 56-1 (continued) Bulbs that have the same trade number have the same operating voltage and wattage. The NA means that the bulb uses a natural amber glass ampoule with clear turn signal lenses.
Chart 56-1 (continued) Bulbs that have the same trade number have the same operating voltage and wattage. The NA means that the bulb uses a natural amber glass ampoule with clear turn signal lenses.

14. Chart 56-1 (continued) Bulbs that have the same trade number have the same operating voltage and wattage. The NA means that the bulb uses a natural amber glass ampoule with clear turn signal lenses.
Chart 56-1 (continued) Bulbs that have the same trade number have the same operating voltage and wattage. The NA means that the bulb uses a natural amber glass ampoule with clear turn signal lenses.

15. REAL WORLD FIX: Weird Problem—Easy Solution A General Motors minivan had the following electrical problems. • The turn signals flashed rapidly on the left side. • With the ignition key off, the lights-on warning chime sounded if the brake pedal was depressed. • When the brake pedal was depressed, the dome light came on. All of these problems were caused by one defective 2057 dual-filament bulb, as shown in - FIGURE 56–3. Apparently, the two filaments were electrically connected when one filament broke and then welded to the other filament. This caused the electrical current to feed back from the brake light filament into the taillight circuit, causing all the problems.
REAL WORLD FIX: Weird Problem—Easy Solution A General Motors minivan had the following electrical problems. • The turn signals flashed rapidly on the left side. • With the ignition key off, the lights-on warning chime sounded if the brake pedal was depressed. • When the brake pedal was depressed, the dome light came on. All of these problems were caused by one defective 2057 dual-filament bulb, as shown in - FIGURE 56–3. Apparently, the two filaments were electrically connected when one filament broke and then welded to the other filament. This caused the electrical current to feed back from the brake light filament into the taillight circuit, causing all the problems.

16. Figure Close-up a 2057 dual-filament (double-contact) bulb that failed. Notice that the top filament broke from its mounting and melted onto the lower filament. This bulb caused the dash lights to come on whenever the brakes were applied.
Figure Close-up a 2057 dual-filament (double-contact) bulb that failed. Notice that the top filament broke from its mounting and melted onto the lower filament. This bulb caused the dash lights to come on whenever the brakes were applied.

17. Figure Corrosion caused the two terminals of this dual-filament bulb to be electrically connected.
Figure Corrosion caused the two terminals of this dual-filament bulb to be electrically connected.

18. Figure 56-5 Often the best diagnosis is a thorough visual inspection
Figure Often the best diagnosis is a thorough visual inspection. This bulb was found to be filled with water, which caused weird problems.
Figure Often the best diagnosis is a thorough visual inspection. This bulb was found to be filled with water, which caused weird problems.

19. Figure This single-filament bulb is being tested with a digital multimeter set to read resistance in ohms. The reading of 1.1 ohms is the resistance of the bulb when cold. As soon as current flows through the filament, the resistance increases about 10 times. It is the initial surge of current flowing through the filament when the bulb is cool that causes many bulbs to fail in cold weather as a result of the reduced resistance. As the temperature increases, the resistance increases.
Figure This single-filament bulb is being tested with a digital multimeter set to read resistance in ohms. The reading of 1.1 ohms is the resistance of the bulb when cold. As soon as current flows through the filament, the resistance increases about 10 times. It is the initial surge of current flowing through the filament when the bulb is cool that causes many bulbs to fail in cold weather as a result of the reduced resistance. As the temperature increases, the resistance increases.

20. Figure Typical brake light and taillight circuit showing the brake switch and all of the related circuit components.
Figure Typical brake light and taillight circuit showing the brake switch and all of the related circuit components.

21. FREQUENTLY ASKED QUESTION: Why Are LEDs Used for Brake Lights
FREQUENTLY ASKED QUESTION: Why Are LEDs Used for Brake Lights? Light-emitting diode (LED) brake lights are frequently used for high-mounted stop lamps (CHMSLs) for the following reasons. 1. Faster illumination. An LED will light up to 200 milliseconds faster than an incandescent bulb, which requires some time to heat the filament before it is hot enough to create light. This faster illumination can mean the difference in stopping distances at 60 mph (100 km/h) by about 18 ft (6 m) due to the reduced reaction time for the driver of the vehicle behind. 2. Longer service life. LEDs are solid-state devices that do not use a filament to create light. As a result, they are less susceptible to vibration and will often last the life of the vehicle. NOTE: Aftermarket replacement LED bulbs that are used to replace conventional bulbs may require the use of a different type of flasher unit due to the reduced current draw of the LED bulbs. - SEE FIGURE 56–8.
FREQUENTLY ASKED QUESTION: Why Are LEDs Used for Brake Lights? Light-emitting diode (LED) brake lights are frequently used for high-mounted stop lamps (CHMSLs) for the following reasons. 1. Faster illumination. An LED will light up to 200 milliseconds faster than an incandescent bulb, which requires some time to heat the filament before it is hot enough to create light. This faster illumination can mean the difference in stopping distances at 60 mph (100 km/h) by about 18 ft (6 m) due to the reduced reaction time for the driver of the vehicle behind. 2. Longer service life. LEDs are solid-state devices that do not use a filament to create light. As a result, they are less susceptible to vibration and will often last the life of the vehicle. NOTE: Aftermarket replacement LED bulbs that are used to replace conventional bulbs may require the use of a different type of flasher unit due to the reduced current draw of the LED bulbs. - SEE FIGURE 56–8.

22. Figure A replacement LED taillight bulb is constructed of many small, individual light-emitting diodes.
Figure A replacement LED taillight bulb is constructed of many small, individual light-emitting diodes.

23. Figure The typical turn signal switch includes various springs and cams to control the switch and to cause the switch to cancel after a turn has been completed.
Figure The typical turn signal switch includes various springs and cams to control the switch and to cause the switch to cancel after a turn has been completed.

24. Figure When the stop lamps and turn signals share a common bulb filament, stop light current flows through the turn signal switch.
Figure When the stop lamps and turn signals share a common bulb filament, stop light current flows through the turn signal switch.

25. Figure When a right turn in signaled, the turn signal switch contacts send flasher current to the right-hand filament and brake switch current to the left-hand filament.
Figure When a right turn in signaled, the turn signal switch contacts send flasher current to the right-hand filament and brake switch current to the left-hand filament.

26. Figure 56-12 Two styles of two-prong flasher units.

27. Figure A hazard warning flasher uses a parallel resistor across the contacts to provide a constant flashing rate regardless of the number of bulbs used in the circuit.
Figure A hazard warning flasher uses a parallel resistor across the contacts to provide a constant flashing rate regardless of the number of bulbs used in the circuit.

28. FREQUENTLY ASKED QUESTION: How Do You Tell What Type of Flasher Is Being Used? The easiest way to know which type of flasher can be used is to look at the type of bulb used in the tail lamps and turn signals. If it is a “wedge” style (plastic base, flat and rectangular), the vehicle has an electronic flasher. If it is a “twist and turn” bayonet-style (brass base) bulb, then either type of flasher can be used.
FREQUENTLY ASKED QUESTION: How Do You Tell What Type of Flasher Is Being Used? The easiest way to know which type of flasher can be used is to look at the type of bulb used in the tail lamps and turn signals. If it is a “wedge” style (plastic base, flat and rectangular), the vehicle has an electronic flasher. If it is a “twist and turn” bayonet-style (brass base) bulb, then either type of flasher can be used.

29. FREQUENTLY ASKED QUESTION: Why Does the Side-Marker Light Alternately Flash? A question that service technicians are asked frequently is why the side-marker light alternately goes out when the turn signal is on, and is on when the turn signal is off. Some vehicle owners think that there is a fault with the vehicle, but this is normal operation. The side-marker light goes out when the lights are on and the turn signal is flashing because there are 12 volts on both sides of the bulb (see points X and Y in - FIGURE 56–14). Normally, the side-marker light gets its ground through the turn signal bulb.
FREQUENTLY ASKED QUESTION: Why Does the Side-Marker Light Alternately Flash? A question that service technicians are asked frequently is why the side-marker light alternately goes out when the turn signal is on, and is on when the turn signal is off. Some vehicle owners think that there is a fault with the vehicle, but this is normal operation. The side-marker light goes out when the lights are on and the turn signal is flashing because there are 12 volts on both sides of the bulb (see points X and Y in - FIGURE 56–14). Normally, the side-marker light gets its ground through the turn signal bulb.

30. Figure The side-marker light goes out whenever there is voltage at both points X and Y. These opposing voltages stop current flow through the side-marker light. The left turn light and left park light are actually the same bulb (usually 2057) and are shown separately to help explain how the side-marker light works on many vehicles.
Figure The side-marker light goes out whenever there is voltage at both points X and Y. These opposing voltages stop current flow through the side-marker light. The left turn light and left park light are actually the same bulb (usually 2057) and are shown separately to help explain how the side-marker light works on many vehicles.

31. Figure 56-15 Typical headlight circuit diagram
Figure Typical headlight circuit diagram. Note that the headlight switch is represented by a dotted outline indicating that other circuits (such as dash lights) also operate from the switch.
Figure Typical headlight circuit diagram. Note that the headlight switch is represented by a dotted outline indicating that other circuits (such as dash lights) also operate from the switch.

32. Figure 56-16 A typical four-headlight system using sealed beam headlights.

33. Figure 56-17 A typical composite headlamp assembly
Figure A typical composite headlamp assembly. The lens, housing, and bulb sockets are usually included as a complete assembly.
Figure A typical composite headlamp assembly. The lens, housing, and bulb sockets are usually included as a complete assembly.

34. TECH TIP: Diagnose Bulb Failure Halogen bulbs can fail for various reasons. Some causes for halogen bulb failure and their indications are as follows: • Gray color. Low voltage to bulb (check for corroded socket or connector) • White (cloudy) color. Indication of an air leak • Broken filament. Usually caused by excessive vibration • Blistered glass. Indication that someone has touched the glass NOTE: Never touch the glass (called the ampoule) of any halogen bulb. The oils from your fingers can cause unequal heating of the glass during operation, leading to a shorter-than-normal service life. - SEE FIGURE 56–18.
TECH TIP: Diagnose Bulb Failure Halogen bulbs can fail for various reasons. Some causes for halogen bulb failure and their indications are as follows: • Gray color. Low voltage to bulb (check for corroded socket or connector) • White (cloudy) color. Indication of an air leak • Broken filament. Usually caused by excessive vibration • Blistered glass. Indication that someone has touched the glass NOTE: Never touch the glass (called the ampoule) of any halogen bulb. The oils from your fingers can cause unequal heating of the glass during operation, leading to a shorter-than-normal service life. - SEE FIGURE 56–18.

35. Figure 56-18 Handle a halogen bulb by the base to prevent the skin’s oil from getting on the glass.

36. Figure The igniter contains the ballast and transformer needed to provide high-voltage pulses to the arc tube bulb.
Figure The igniter contains the ballast and transformer needed to provide high-voltage pulses to the arc tube bulb.

37. FREQUENTLY ASKED QUESTION: What Is the Difference Between the Temperature of the Light and the Brightness of the Light? The temperature of the light indicates the color of the light. The brightness of the light is measured in lumens. A standard 100 watt incandescent light bulb emits about 1,700 lumens. A typical halogen headlight bulb produces about 2,000 lumens, and a typical HID bulb produces about 2,800 lumens.
FREQUENTLY ASKED QUESTION: What Is the Difference Between the Temperature of the Light and the Brightness of the Light? The temperature of the light indicates the color of the light. The brightness of the light is measured in lumens. A standard 100 watt incandescent light bulb emits about 1,700 lumens. A typical halogen headlight bulb produces about 2,000 lumens, and a typical HID bulb produces about 2,800 lumens.

38. Figure HID (xenon) headlights emit a whiter light than halogen headlights and usually look blue compared to halogen bulbs.
Figure HID (xenon) headlights emit a whiter light than halogen headlights and usually look blue compared to halogen bulbs.

39. WARNING: Always adhere to all warnings because the highvoltage output of the ballast assembly can cause personal injury or death.
WARNING: Always adhere to all warnings because the highvoltage output of the ballast assembly can cause personal injury or death.

40. Figure LED headlights usually require multiple units to provide the needed light as seen on this Lexus LS600h.
Figure LED headlights usually require multiple units to provide the needed light as seen on this Lexus LS600h.

41. Figure 56-22 Typical headlight aiming diagram as found in service information.

42. Figure Many composite headlights have a built-in bubble level to make aiming easy and accurate.
Figure Many composite headlights have a built-in bubble level to make aiming easy and accurate.

43. Figure Adaptive front lighting systems rotate the low-beam headlight in the direction of travel.
Figure Adaptive front lighting systems rotate the low-beam headlight in the direction of travel.

44. Figure A typical adaptive front lighting system uses two motors: one for the up and down movement and the other for rotating the low-beam headlight to the left and right.
Figure A typical adaptive front lighting system uses two motors: one for the up and down movement and the other for rotating the low-beam headlight to the left and right.

45. Figure Typical dash-mounted switch that allows the driver to disable the front lighting system.
Figure Typical dash-mounted switch that allows the driver to disable the front lighting system.

46. TECH TIP: Checking a Dome Light Can Be Confusing If a technician checks a dome light with a test light, both sides of the bulb will “turn on the light” if the bulb is good. This will be true if the system’s “ground switched” doors are closed and the bulb is good. This confuses many technicians because they do not realize that the ground will not be sensed unless the door is open.
TECH TIP: Checking a Dome Light Can Be Confusing If a technician checks a dome light with a test light, both sides of the bulb will “turn on the light” if the bulb is good. This will be true if the system’s “ground switched” doors are closed and the bulb is good. This confuses many technicians because they do not realize that the ground will not be sensed unless the door is open.

47. Figure 56-27 Typical daytime running light (DRL) circuit
Figure Typical daytime running light (DRL) circuit. Follow the arrows from the DRL module through both headlights. Notice that the left and right headlights are connected in series, resulting in increased resistance, less current flow, and dimmer than normal lighting. When the normal headlights are turned on, both headlights receive full battery voltage, with the left headlight grounding through the DRL module.
Figure Typical daytime running light (DRL) circuit. Follow the arrows from the DRL module through both headlights. Notice that the left and right headlights are connected in series, resulting in increased resistance, less current flow, and dimmer than normal lighting. When the normal headlights are turned on, both headlights receive full battery voltage, with the left headlight grounding through the DRL module.

48. Figure Most vehicles use positive switching of the high- and low-beam headlights. Notice that both filaments share the same ground connection. Some vehicles use negative switching and place the dimmer switch between the filaments and the ground.
Figure Most vehicles use positive switching of the high- and low-beam headlights. Notice that both filaments share the same ground connection. Some vehicles use negative switching and place the dimmer switch between the filaments and the ground.

49. Figure 56-29 A typical courtesy light doorjamb switch
Figure A typical courtesy light doorjamb switch. Newer vehicles use the door switch as an input to the vehicle computer and the computer turns the interior lights on or off. By placing the lights under the control of the computer, the vehicle engineers have the opportunity to delay the lights after the door is closed and to shut them off after a period of time to avoid draining the battery.
Figure A typical courtesy light doorjamb switch. Newer vehicles use the door switch as an input to the vehicle computer and the computer turns the interior lights on or off. By placing the lights under the control of the computer, the vehicle engineers have the opportunity to delay the lights after the door is closed and to shut them off after a period of time to avoid draining the battery.

50. Figure An automatic dimming mirror compares the amount of light toward the front of the vehicle to the rear of the vehicle and allies a voltage to cause the gel to darken the mirror.
Figure An automatic dimming mirror compares the amount of light toward the front of the vehicle to the rear of the vehicle and allies a voltage to cause the gel to darken the mirror.

51. FREQUENTLY ASKED QUESTION: What Is the Troxler Effect
FREQUENTLY ASKED QUESTION: What Is the Troxler Effect? The Troxler effect, also called Troxler fading, is a visual effect where an image remains on the retina of the eye for a short time after the image has been removed. The effect was discovered in 1804 by Igney Paul Vital Troxler (1780–1866), a Swiss physician. Because of the Troxler effect, headlight glare can remain on the retina of the eye and create a blind spot. At night, this fading away of the bright lights from the vehicle in the rear reflected by the rearview mirror can cause a hazard.
FREQUENTLY ASKED QUESTION: What Is the Troxler Effect? The Troxler effect, also called Troxler fading, is a visual effect where an image remains on the retina of the eye for a short time after the image has been removed. The effect was discovered in 1804 by Igney Paul Vital Troxler (1780–1866), a Swiss physician. Because of the Troxler effect, headlight glare can remain on the retina of the eye and create a blind spot. At night, this fading away of the bright lights from the vehicle in the rear reflected by the rearview mirror can cause a hazard.

52. TECH TIP: The Weirder the Problem, the More Likely It Is a Poor Ground Connection Bad grounds are often the cause for feedback or lamps operating at full or partial brilliance. At first the problem looks weird because often the switch for the lights that are on dimly is not even turned on. When an electrical device is operating and it lacks a proper ground connection, the current will try to find ground and will often cause other circuits to work. Check all grounds before replacing parts.
TECH TIP: The Weirder the Problem, the More Likely It Is a Poor Ground Connection Bad grounds are often the cause for feedback or lamps operating at full or partial brilliance. At first the problem looks weird because often the switch for the lights that are on dimly is not even turned on. When an electrical device is operating and it lacks a proper ground connection, the current will try to find ground and will often cause other circuits to work. Check all grounds before replacing parts.

53. TAILLIGHT BULB REPLACEMENT 1 The driver noticed that the taillight fault indicator (icon) on the dash was on any time the lights were on.
TAILLIGHT BULB REPLACEMENT 1 The driver noticed that the taillight fault indicator (icon) on the dash was on any time the lights were on.

54. TAILLIGHT BULB REPLACEMENT 2 A visual inspection at the rear of the vehicle indicated that the right rear taillight bulb did not light. Removing a few screws from the plastic cover revealed the taillight assembly.
TAILLIGHT BULB REPLACEMENT 2 A visual inspection at the rear of the vehicle indicated that the right rear taillight bulb did not light. Removing a few screws from the plastic cover revealed the taillight assembly.

55. TAILLIGHT BULB REPLACEMENT 3 The bulb socket is removed from the taillight assembly by gently twisting the base of the bulb counterclockwise.
TAILLIGHT BULB REPLACEMENT 3 The bulb socket is removed from the taillight assembly by gently twisting the base of the bulb counterclockwise.

56. TAILLIGHT BULB REPLACEMENT 4 The bulb is removed from the socket by gently grasping the bulb and pulling the bulb straight out of the socket. Many bulbs required that you rotate the bulb 90° (1/4 turn) to release the retaining bulbs.
TAILLIGHT BULB REPLACEMENT 4 The bulb is removed from the socket by gently grasping the bulb and pulling the bulb straight out of the socket. Many bulbs required that you rotate the bulb 90° (1/4 turn) to release the retaining bulbs.

57. TAILLIGHT BULB REPLACEMENT 5 The new 7443 replacement bulb is being checked with an ohmmeter to be sure that it is okay before it is installed in the vehicle.
TAILLIGHT BULB REPLACEMENT 5 The new 7443 replacement bulb is being checked with an ohmmeter to be sure that it is okay before it is installed in the vehicle.

58. TAILLIGHT BULB REPLACEMENT 6 The replacement bulb in inserted into the taillight socket and the lights are turned on to verify proper operation before putting the components back together.
TAILLIGHT BULB REPLACEMENT 6 The replacement bulb in inserted into the taillight socket and the lights are turned on to verify proper operation before putting the components back together.

59. OPTICAL HEADLIGHT AIMING 1 Before checking the vehicle for headlight aim, be sure that all the tires are at the correct inflation pressure, and that the suspension is in good working condition.
OPTICAL HEADLIGHT AIMING 1 Before checking the vehicle for headlight aim, be sure that all the tires are at the correct inflation pressure, and that the suspension is in good working condition.

60. OPTICAL HEADLIGHT AIMING 2 The headlight aim equipment will have to be adjusted for the slope of the floor in the service bay. Start the process by turning on the laser light generator on the side of the aimer body.
OPTICAL HEADLIGHT AIMING 2 The headlight aim equipment will have to be adjusted for the slope of the floor in the service bay. Start the process by turning on the laser light generator on the side of the aimer body.

61. OPTICAL HEADLIGHT AIMING 3 Place a yardstick or measuring tape vertically in front of the center of the front wheel, noting the height of the laser beam.
OPTICAL HEADLIGHT AIMING 3 Place a yardstick or measuring tape vertically in front of the center of the front wheel, noting the height of the laser beam.

62. OPTICAL HEADLIGHT AIMING 4 Move the yardstick to the center of the rear wheel and measure the height of the laser beam at this point. The height at the front and rear wheels should be the same.
OPTICAL HEADLIGHT AIMING 4 Move the yardstick to the center of the rear wheel and measure the height of the laser beam at this point. The height at the front and rear wheels should be the same.

63. OPTICAL HEADLIGHT AIMING 5 If the laser beam height measurements are not the same, the floor slope of the aiming equipment must be adjusted. Turn the floor slope knob until the measurements are equal.
OPTICAL HEADLIGHT AIMING 5 If the laser beam height measurements are not the same, the floor slope of the aiming equipment must be adjusted. Turn the floor slope knob until the measurements are equal.

64. OPTICAL HEADLIGHT AIMING 6 Place the aimer in front of the headlight to be checked, at a distance of 10 to 14 inches (25 to 35 cm). Use the aiming pointer to adjust the height of the aimer to the middle of the headlight.
OPTICAL HEADLIGHT AIMING 6 Place the aimer in front of the headlight to be checked, at a distance of 10 to 14 inches (25 to 35 cm). Use the aiming pointer to adjust the height of the aimer to the middle of the headlight.

65. OPTICAL HEADLIGHT AIMING 7 Align the aimer horizontally, using the pointer to place the aimer at the center of the headlight.
OPTICAL HEADLIGHT AIMING 7 Align the aimer horizontally, using the pointer to place the aimer at the center of the headlight.

66. OPTICAL HEADLIGHT AIMING 8 Lateral alignment (aligning the body of the aimer with the body of the vehicle) is done by looking through the upper visor. The line in the upper visor is aligned with symmetrical points on the vehicle body.
OPTICAL HEADLIGHT AIMING 8 Lateral alignment (aligning the body of the aimer with the body of the vehicle) is done by looking through the upper visor. The line in the upper visor is aligned with symmetrical points on the vehicle body.

67. OPTICAL HEADLIGHT AIMING 9 Turn on the vehicle headlights, being sure to select the 9 correct beam position for the headlight to be aimed.
OPTICAL HEADLIGHT AIMING 9 Turn on the vehicle headlights, being sure to select the 9 correct beam position for the headlight to be aimed.

68. OPTICAL HEADLIGHT AIMING View the light beam through the aimer window. The position of the light pattern will be different for high and low beams.
OPTICAL HEADLIGHT AIMING View the light beam through the aimer window. The position of the light pattern will be different for high and low beams.

69. OPTICAL HEADLIGHT AIMING If the first headlight is aimed adequately, move the aimer to the headlight on the opposite side of the vehicle. Follow the previous steps to position the aimer accurately.
OPTICAL HEADLIGHT AIMING If the first headlight is aimed adequately, move the aimer to the headlight on the opposite side of the vehicle. Follow the previous steps to position the aimer accurately.

70. OPTICAL HEADLIGHT AIMING If adjustment is required, move the headlight adjusting screws using a special tool or a 1/4-in. drive ratchet/socket combination. Watch the light beam through the aimer window to verify the adjustment.
OPTICAL HEADLIGHT AIMING If adjustment is required, move the headlight adjusting screws using a special tool or a 1/4-in. drive ratchet/socket combination. Watch the light beam through the aimer window to verify the adjustment.