Theory Of Operation - Hazards

The hazard warning system includes the IPC, the BCM and the hazard switch. The switch is located at the top of the center stack display unit. The hazard switch provides a hardwired output to the BCM. The BCM monitors the hazard switch input through an internal pull-up. When the BCM receives an input from the hazard switch it controls hazard warning system operation and flash rate by controlling battery voltage outputs through high side drivers on the right and left turn signal feed circuits. The BCM also sends the appropriate electronic messages to the IPC overt the CAN data bus to control the illumination and flash rate of the right and left turn signal indicators, as well as to control the click rate of an electromechanical relay soldered to the IPC electronic circuit board that emulates the sound emitted by a conventional hazard warning flasher. The IPC then sends messages to the center stack display unit over the LIN data bus to control the illumination of the hazard switch push button.