RAM 1500 Truck 4WD V8-5.9L VIN Z (2002)
Hazard Warning Switch: Description and Operation
HAZARD SWITCH
The hazard switch is activated by a push button located in the multifunction switch on the top of the steering column between the steering wheel
and instrument cluster.
The hazard warning system allows the vehicle operator to provide other vehicle operators in the near proximity an optical indication that the
vehicle is disabled or an obstacle to traffic flow. The hazard warning system has battery voltage at all times, regardless of ignition position.
The instrument cluster monitors the multiplexed multifunction switch operation. When the hazard warning switch is activated, the instrument
cluster will send a J1850 bus message to the Front Control Module (FCM), then activate the two turn signal indicators and audible click in the
instrument cluster.
The FCM will then activate the necessary relays in the Power Distribution Center (PDC) to begin flashing both the front and rear turn signal
indicator lamps.
MULTI-FUNCTION SWITCH
Turn Signal System
The multi-function switch is a resistive MUX switch that is monitored by the Instrument Cluster. The turn signals are actuated with the lever on
Multi-Function Switch. The signals are automatically turned OFF by a canceling cam (two lobes molded to the back of the clock spring
mechanism). The cam comes in contact with the cancel actuator on the turn signal (multi-function) switch assembly. Either cam lobe, pushing on
the cancel actuator, returns the switch to the OFF position.
The Instrument Cluster monitors the multiplexed multifunction switch. In a turning event the Instrument Cluster senses a change in the turn signal
lever and illuminates the appropriate turn signal indicator. At the same time, the Instrument Cluster will send a J1850 message on the PCI bus to
the Front Control Module (FCM). The FCM will respond by activating the appropriate relay in the Power Distribution Center.
A chime will sound after the turn is completed if vehicle has traveled a distance of approximately 1.0 mile and a speed of 15 mph, with the turn
signal ON.
