Commander 4WD V6-3.7L VIN K (2007)
Hazard Warning Switch: Description and Operation
Operation
OPERATION
The hazard switch features a push-push type latching push button. When the push button is in its latched (lowered) position the switch contacts are open,
and when the push button is in its unlatched (raised) position the switch contacts are closed. Although the hazard switch is mounted to the SCM, the
hazard switch circuits only pass through the SCM. The SCM has no control over and does not monitor the hazard switch output.
The hazard switch receives a ground on one terminal and provides a ground signal output to the Front Control Module (FCM) whenever the switch
contacts are closed. The FCM responds to this input by controlling a battery voltage output and the flash rate for each of the right and left turn signal
lamps, then sends an electronic hazard switch status message over the Controller Area Network (CAN) data bus to the ElectroMechanical Instrument
Cluster (EMIC) (also known as the Cab Compartment Node/CCN) 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 onto the EMIC electronic circuit board that emulates the sound emitted by a
conventional hazard warning flasher.
The hazard switch as well as the hard wired inputs and outputs of the switch may be diagnosed using conventional diagnostic tools and procedures. Refer
to the appropriate wiring information.
