Operation

OPERATION

AUTOMATIC HEADLAMPS

The optional automatic headlamp (auto low) system includes the Steering Control Module (SCM), the Totally Integrated Power Module (TIPM), and the left (lighting) multi-function switch. The A (Automatic) position must be selected using the left multi-function switch.

Once this prerequisite has been met, the SCM responds by sending the appropriate electronic lighting request messages to the FCM over the Controller Area Network (CAN) data bus and an ambient light level input to the ElectroMechanical Instrument Cluster (EMIC) (also known as the Cab Compartment Node/CCN) which is relayed to the FCM over the CAN data bus. With the engine running, the FCM responds to these messages by automatically controlling a pulse width modulated voltage output to the selected headlamp bulbs through the right and left low beam feed circuits to illuminate the headlamps. The FCM also sends the appropriate electronic messages back to the EMIC/CCN to control the illumination of the high beam indicator.

DAYTIME RUNNING LAMPS (CANADA ONLY)

Vehicles equipped with the Daytime Running Lamps (DRL) feature illuminate the high beam filament of both headlamp bulbs at a reduced intensity when the engine is running, the parking brake is released, the headlamps are turned OFF, and the optional automatic transmission gear selector lever is in any position except PARK. The park lamps may be ON or OFF for DRL to operate. For vehicles with a manual transmission, the DRL will operate in any transmission gear selector lever position. The TIPM must be programmed appropriately for this feature to be enabled.

Once enabled, anytime the TIPM receives electronic messages over the CAN data bus from the Powertrain Control Module (PCM) indicating the engine is running, from the ElectroMechanical Instrument Cluster (EMIC) (also known as the Cab Compartment Node/CCN) indicating the status of the left (lighting) multi-function switch is in any position except headlamps ON and the parking brake lever is released, and from the Transmission Control Module (TCM) indicating the automatic transmission gear selector lever is in any position except PARK, the TIPM provides a pulse width modulated voltage output to the headlamp high beam bulb filaments through high side drivers on the right and left high beam feed circuits to produce illumination at a reduced intensity.