Operation

OPERATION

AUTOMATIC HEADLAMP SYSTEM


Automatic headlamps are controlled by the Totally Integrated Power Module (TIPM). With the headlamp switch in the AUTO position, the TIPM will control the headlamp, parking, side marker, tail and instrumentation lamps based on ambient light levels. Ambient light levels are measured by the HVAC module and communicated to the CCN as a voltage level in a CAN I-HS message. The CCN then compares the voltage level to a threshold and communicates an Automatic Headlamp ON/Off message to the TIPM in a CAN I-HS messages TIPM turns on the exterior lights based upon the headlamp switch setting, the CCN automatic headlamp request and the engine running state. Ambient light readings are averaged to limit cycling the lamps ON and OFF when passing through areas with varying light levels. The automatic headlamps will only function when the engine is running.

DAYTIME RUNNING LAMPS


Power is reduced using pulse-width modulation to the high beams, where by the power is switched on and off rapidly instead of remaining on continuously. The duration and interval of the power pulses is programmed into the TIPM. Daytime running lamps are functional when 450 rpm's are reached.

HEADLAMP SYSTEM


The headlamp system will default to the headlamps ON mode when the ignition switch is ON and CAN I-HS communications has failed between the CCN and the TIPM. The system will return to normal operation when the open or short is repaired. A fault will be reported by the CCN hen a failure occurs on the dimmer or headlamp switch input. Should any communication issues occur between the CCN and the TIPM, the TIPM will log communication faults against the CCN.

If the exterior lamps are ON and the headlamp switch is in any position other than OFF or AUTO and with the ignition switch OFF (LOCK), the headlamps, fog lamps and park/tail lamps will be turned off by the TIPM after 8 minutes. This will only occur if the headlamp switch is turned to the off position prior to the 8 minute time out. This feature prevents the vehicle battery from being discharged when the vehicle lights have been left ON. Park lamp load shedding is disabled in some markets.

HEADLAMP TIME DELAY SYSTEM


The headlamp time delay system is activated by turning the headlamps ON (high or low beam) while the engine is running, turning the ignition switch OFF, and then turning the headlamp switch OFF within 45 seconds. The system will not activate if more than 45 seconds elapse between ignition switch OFF and headlamp switch OFF. The TIPM will allow the headlamps to remain ON for 90 seconds (configurable) before they automatically turn off (If the key is in the ignition during the headlamp time delay mode, then both the headlamps and park lamps (including panel dimming) will be ON). When the headlamp switch is in the AUTO position (Automatic mode), the Headlamp Time Delay system will function when the ignition switch is placed in any position other than run/start.

If the headlamp switch is in the Auto Headlamp Position, the headlamps are ON due to the night signal from the CMTC and the ignition is in any position other than run/start, the TIPM shall enter a 90 second (configurable) Auto Headlamps time delay mode. If the key is in the ignition during the headlamp time delay mode, then both the headlamps and park lamps (including panel dimming) will be ON. If the FOBIK is not in the ignition, then only the headlamps will be ON. The TIPIM will allow the headlamps to remain ON for 90 seconds before they automatically turn OFF.

OPTICAL HORN/HIGH BEAMS


When the multi-function switch is pulled to the first detent (optical horn) signal, the headlamps are ON, key-in the ignition, the CCN shall send a message via PCI bus to the TIPM to turn on the headlamps drivers to illuminate all four filaments (Low and High beams). When the multi-function switch is pulled to the second detent (high beam) signal and the headlamps are ON, the CCN shall send a message via PCI bus to the TIPM to turn on the headlamps drivers. The High Beams are illuminated and the Low Beams and Fog Lamps (if ON) are extinguished. If the headlamps were in the high beam configuration when power was removed from the headlamps, the headlamps will be configured as low beam the next time they are activated. The time overlap when both the high beams and low beams are simultaneously on is limited to 0.2 seconds (to protect the bulb life). The low beams will drop out if the optical horn is activated for longer than 0.2 seconds. The CCN reads the switch and the messages are sent to the TIPM.

NOTE: For RT BUX- Export vehicles, the low beams and front fog lamps will remain ON when high beams are activated.