Lighting and Horns: Description and Operation
LAMP/LIGHTING - EXTERIORFig. 2 Brake Lamp Switch:
BRAKE LAMP SWITCH
The brake lamp switch is located under the instrument panel, at the brake pedal arm (Fig 2). It has three internal switches controlling various functions of the vehicle. It's main function is to control operation of the vehicle's brake lamps. Other functions include speed control deactivation, brake sense for the antilock brake system and brake sense for the brake transmission shift interlock.
CAUTION: The switch can only be adjusted once. That is during initial installation of the switch. If the switch is not adjusted properly or has been removed for some service, a new switch must be installed and adjusted.
When the brake pedal is pressed, the plunger on the outside of the brake lamp switch extends outward. This action opens or closes the contacts of the three switches inside the brake lamp switch.
With the brake pedal pressed down (plunger extended), the switch for terminals 1 and 2 is closed completing the circuit. The switch for terminals 3 and 4 is open and so is the switch for 5 and 6. When the brake pedal is released (plunger pushed in), the three switches assume the opposite positions. The switch for terminals 1 and 2 is now open while the other two switches are now closed, completing their circuits.
Fig. 8 Combination Flasher:
COMBINATION FLASHER
The turn signal flasher and the hazard warning flasher are combined into one unit called a Combination Flasher (combo-flasher). The combo-flasher is a smart relay located on the back of the multi-function switch. The combo-flasher is black in color and has a dampener material wrapped on it.
The combo-flasher controls the flashing of the hazard warning system and the turn signal system. Constant battery voltage is supplied to the flasher so that it can perform the hazard warning function, and ignition switched battery voltage is supplied for the turn signal function. However, when the flasher is idle no current is drawn through the module. The unit does not become active until it is provided a signal ground from the turn signal switch or hazard warning switch. An inoperative bulb or incomplete turn signal circuit will cause the flasher rate to double. Typical flash rate is about ninety flashes per minute. When a bulb is burnt out, or when a circuit for a lamp is open, the turn signal flash rate will increase to a minimum of 180 flashes per minute. However, an open lamp circuit or burnt out bulb does not change the hazard warning flash rate.
Turn signal inputs that actuate the combination flasher are low current grounds, each drawing a maximum of 300 milliamperes. The turn signal inputs are provided to the flasher through the multi-function switch on the steering column. The hazard warning signal input is a low current ground drawing a maximum of 600 milliamperes. The hazard warning input can be provided through the multi-function switch on the steering column.
DAYTIME RUNNING LAMP MODULE
Vehicles built for use in Canada are equipped with a Daytime Running Lamp (DRL) system. Turn signal lamp circuitry always comes from the multi-function switch, and goes to the cluster connector, into the cluster, then back out to the front turn signal switch lamps.
The Canadian cluster provides steady illumination of the front turn signal when the ignition switch is in the ON position. The DRL function may be inhibited by activating the turn signals, the hazard flashers, the headlamp switch, or park brake.
Fig. 11 Front Position Lamp Location - Export:
FRONT POSITION LAMP - EXPORT
On vehicles equipped with front position lamps, it is incorporated into each of the headlamp units. Front position lamps utilize a clear lens and clear bulb (Refer to ELECTRICAL/LAMPS/ LIGHTING - EXTERIOR - SPECIFICATIONS).
The front position lamps are turned ON or OFF with the headlamp switch which is incorporated in the multi-function switch.
HEADLAMP LEVELING MOTOR - EXPORT
The Headlamp Leveling System allows the driver to adjust the headlamp beam pattern from the interior of the vehicle to compensate for passenger or cargo load. Only the vertical axis of the headlamp beam can be adjusted.
A headlamp leveling switch is located on the instrument panel and controls the headlamp leveling motors found on the headlamp unit. The headlamp leveling switch has four settings 0 - 3, 0 being the lowest, 3 being the highest headlight beam vertical setting.
When performing a headlamp beam pattern alignment on a vehicle equipped with headlamp leveling, be certain the headlamp leveling switch is in the "0" position before starting. Failure to do so will result in and incorrect headlamp unit alignment.
With the rotation of the headlamp leveling switch control knob, voltage is adjusted at the headlamp leveling switch (rheostat). This signals the headlamp leveling motors to adjust the vertical headlamp beam pattern accordingly Headlamps must be ON in order for the leveling system to function.
Fig. 22 Headlamp Leveling Switch:
HEADLAMP LEVELING SWITCH - EXPORT
This Headlamp Leveling Switch is located in the accessory switch bezel (Fig 22) located on the instrument panel. The switch is the primary controller of the headlamp leveling system. The leveling switch has four settings 0 - 3, 0 being the lowest, and 3 being the highest headlight beam vertical setting.
With the rotation of the headlamp leveling switch control knob, voltage is adjusted at the headlamp leveling switch (rheostat). This signals the headlamp leveling motors (headlamp unit mounted) to adjust the vertical headlamp beam pattern accordingly. Headlamps must be ON in order for the leveling system to function.
Fig. 26 Multi-Function Switch:
HEADLAMP SWITCH
The headlamp switch is integral to the left stalk of the multi-function switch (Fig 26) on the steering column, behind the steering wheel. A knob on the end of the left control stalk controls all of the exterior lighting functions.
Turn the end of the control lever to the first detent for parking light operation and for headlamp operation, to the second detent. To activate the front fog lights, turn ON the parking lights or the low beam headlights and pull out the end of the control lever.
The headlamp switch is part of the multi-function switch (Refer to ELECTRICAL/LAMPS/LIGHTING EXTERIOR/MULTI-FUNCTION SWITCH - DIAGNOSIS AND TESTING). The headlamp switch cannot be repaired. If found defective, it must be replaced.
Fig. 26 Multi-Function Switch:
MULTI-FUNCTION SWITCH
The turn signals are part of the multi-function switch which contains:
- Electrical circuitry for turn signals
- Hazard warning switch
- Headlamp switch
- Fog Lamp Switch
- Headlamp beam select switch
- Optical Horn
- Instrument Panel Lamp Dimmer/Interior Lamp Switch
- Combination Flasher
The integrated turn signal switch assembly is mounted to the left hand side of the steering column.
When the driver wishes to signal his intentions to change direction of travel, he moves the lever upward to cause the right signals to flash and downward to cause the left signals to flash. After completion of a turn the system is deactivated automatically As the steering wheel returns to the straight ahead position, a canceling cam molded to the clockspring mechanism comes in contact with the cancel actuator on the turn signal multi-function switch assembly The cam lobe, pushing on the cancel actuator, returns the switch to the off position.
If only momentary signaling such as indication of a lane change is desired, the switch is actuated to a left or right intermediate detent position. In this position the signal lamps flash as described above, but the switch returns to the OFF position as soon as the lever is released.
When the system is activated, one of two indicator lamps mounted in the instrument cluster flashes in unison with the turn signal lamps, indicating to the driver that the system is operating.
Hazard Warning System
The hazard warning system is actuated by a push button located in the multi-function switch on the top of the steering column between the steering wheel and the instrument panel. The hazard switch is identified with a double triangle on front of the button.
The hazard warning system allows the vehicle operator to provide the drivers of other vehicles in near proximity an optical indication that the vehicle is disabled or is an obstacle to traffic flow. Unlike the turn signal system, the hazard warning system has battery current at all times, regardless of ignition switch position.
When the hazard warning system is activated, the combination flasher will cause both the right and left side turn signal indicator lamps, front park/turn signal lamps, front side marker lamps and rear turn signal lamps to flash ON and OFF. If the exterior lamps are turned OFF, the front park/turn signal lamps and the front side marker lamps will flash in unison. If the exterior lamps are turned ON, the front park/turn signal lamps and the side marker lamps will flash alternately.
Fig. 34 Multi-Function Switch With Rear Fog Lamp - Export:
REAR FOG LAMP SWITCH - EXPORT
The rear fog lamp switch is incorporated into the multi-function switch (Fig. 34).
The multi-function switch contains the added circuitry for the operation of the rear fog lamp switch. While in the front fog lights position, rotate the end of the left control stalk past the headlights (Refer to ELECTRICAL/LAMPS/LIGHTING EXTERIOR/MULTI- FUNCTION SWITCH DIAGNOSIS AND TESTING) position to activate the rear fog lights for rear fog lamp diagnosis.