Hazard Warning Lamps: Description and Operation
TURN SIGNAL SYSTEMFig.1 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 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.
HEADLAMP SWITCH
The headlamp switch is integral to the left stalk of the multi-function switch located 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. Turn to the second detent for headlight operation. 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 Multi-Function Switch Diagnosis and Testing, Turn Signal and Hazard Warning Flasher Diagnosis table. The headlamp switch cannot be repaired. If found defective, it must be replaced.
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. Constant battery voltage is supplied to the flasher so that it can perform the hazard warning function, and ignitor 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.
The combo-flasher controls the flashing of the hazard warning system and the turn signal system. 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 multifunction 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 multifunction switch on the steering column.