K 1500 Truck 4WD V8-6.5L DSL Turbo VIN S (1999)
Body Control Module: Description and Operation
Wake-Up State
Wake-Up signals that will turn the BCM on and cause it to begin active control and/or monitoring certain devices. The BCM wake-ups are:
Door ajar switches
Door handle switches
Dome lamp
Park lamps
Power door lock switches
Interior lamp request active
Ignition key put into the ignition switch
Ignition key removed from the ignition switch
Ignition in the run position key in door lock switch
Liftgate release switch
Liftgate jamb switch
Remote control door lock transmitter request to the BCM
Asleep States
The BCM is Asleep when it has stopped controlling or monitoring devices and has become idle again. After the ignition switch is turned to the lock
position and 20 minutes (1216 seconds) elapse without any wake-up signals, the BCM enters into a sleep state and goes into the low power mode. If the
BCM is in low power mode and detects a wake-up command, the BCM will enter into the wake-up state and enter the high power mode. If the vehicle
has been left inactive (ignition in the lock position and no BCM wake-ups) for 20 minutes, the BCM will return to the low power mode.
Remote Panic Alarm
The head lamps and the horn will be activated after pressing the horn button on the remote control door lock transmitter. Press the horn button again to
de-activate the head lamps and the horn. Pressing the horn button only once on the remote control door lock transmitter will activate the head lamps and
the horn for 30 seconds or until the ignition switch is turned to the run position.
Battery Run Down Protection
The battery run down protection provides protection against parasitic loads and excessive battery drain and high current loads related to the courtesy
lamp circuit. The battery run down protection will also protect the battery against being run down from the courtesy lamp circuit to the level which will
not allow the vehicle to start. The BCM will turn off the courtesy lamp circuit after the ignition switch is turned from the run position to the off position
and 20 minutes (1216 seconds) have elapsed and without a lamp request input. In order to return the BCM to normal operation once the battery run
down protection has shut the interior lamps off, the ignition switch is cycled from off position to the on position.
Inadvertent Power Relay
The BCM turns off inadvertent power relay after 20 minutes (1216 seconds) to preserve battery power. The 20 minute timer starts after any one of the
following:
^
Ignition switch is turned from run or start to unlock, lock or ACC.
^
Illuminated entry is activated
^
Interior lamps switch is turned on
^
The liftgate is opened or closed
^
Underhood lamp is activated
^
Vanity lamp is activated
^
Courtesy lamp is activated
^
Dome lamp is activated
^
Glove box lamp is activated
^
Reading lamp is activated
^
Inside rearview mirror lamp is activated.
If any one of the below inputs occur during the 20 minute timer period, the timer is reset to 20 minutes (1216 seconds).
^
Ignition switch is turned from run or start to unlock, lock or ACC.
^
Illuminated entry is activated
^
Interior lamps switch is turned on
^
The liftgate is opened or closed
^
Courtesy lamp is activated
^
Dome lamp is activated
Retained Accessory Power (RAP)
The RAP feature allows the power windows, the radio and the front and rear wiper systems to be operated after the ignition switch is turned from run
position to the lock position, provided that the vehicle's battery voltage is above the minimum voltage threshold when the ignition switch is turned to the
off position. The power windows,radio and the front and rear wiper systems will be turned off when any door is opened or after 10 minutes (599
seconds) have elapsed since the last ignition switch transition.
Illuminated Entry
