Hazard Warning Switch: Description and Operation

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.