Turn Signals: Description and Operation
TURN SIGNAL SYSTEMThe Turn Signal System consists of the Multi-Function Switch, Combination Flasher, and Turn Signal Lamps.
With the ignition switch in the ON position, and the multi-function switch control lever moved up (right turn) or down (left turn), the turn signal system is activated.
When the turn signal system is activated, the selected (right or left) turn signal indicator lamp, front park/turn signal lamp, front side marker lamp, and rear tail/stop/turn signal lamp bulbs will flash.
The switch has a detent position in each direction that provides turn signals with automatic cancellation, and an intermediate momentary position that provides turn signals only until the multi-function switch lever is released.
When the turn signal switch is in a detent position, it is turned off by one of two cancelling cam lobes molded into the hub of the clockspring mechanism. When turning the steering wheel causes one of the cam lobes to contact a cancel actuator in the multi-function switch, the turn signal switch automatically returns to the OFF position.
COMBINATION FLASHER
The combination flasher is a smart relay that functions as both the turn signal system and hazard warning system flasher. The combination flasher is designed to handle the current flow requirements of the factory installed lighting.
If supplemental lighting is added to the turn signal lamp circuits, such as when towing a trailer with lights, the combination flasher will automatically compensate. This allows the flash rate to remain the same, regardless of electrical load increases. However, if a bulb fails in the turn signal lamp circuits, the flash rate of the remaining bulbs in that circuit will increase to 120 flashes-per-minute, or higher.
While the combination flasher shares the terminal orientation (footprint) of a International Standards Organization (ISO)-type relay, the internal circuitry is much different. The combination flasher contains active electronic integrated circuitry elements. Do not substitute any other relay for the combination flasher.
Because of the active electronic elements within the combination flasher, it cannot be tested with conventional automotive electrical test equipment. If the combination flasher is believed to be faulty, test the turn signal and hazard warning system circuits as described. Then replace the combination flasher with a known good unit to confirm system operation.
The combination flasher cannot be repaired and, if faulty, it must be replaced.
HAZARD WARNING SYSTEM
The Hazard Warning System consists of the Hazard Switch, Combination Flasher, Multi-Function Switch, and Turn Signal Lamps.
The hazard warning system is actuated by a push button located 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 top of the button.
Push the button to turn the hazard warning system ON and push the button again to turn the system OFF.
When the hazard warning system is activated, both turn signal indicator lamps in the message center flash in unison with the turn signal lamps, indicating to the driver that the system is operating.
Multi-Function Switch:
MULTI-FUNCTION SWITCH
The multi-function switch assembly is mounted to the left side of the steering column. This switch contains circuitry for the following functions:
- Turn signals
- Hazard warning
- Headlamp beam selection
- Headlamp optical horn
- Windshield wipers
- Windshield washers.
The information contained addresses only the switch functions for the turn signal and hazard warning circuits. For information relative to the other switch functions. However, the multi-function switch cannot be repaired. If any function of the switch is faulty, the entire switch assembly must be replaced.
TURN SIGNAL INDICATOR LAMPS
The turn signal indicator lamps are located in the instrument cluster.
They flash with the exterior turn signal lamps to give the driver a visual indication that a turn signal or the hazard warning system is operating.