Jeep 1997 Grand Cherokee Service Manual page 1336

8W - 45 - 12
DESCRIPTION AND OPERATION
A/C SELECT SWITCH . . . . . . . . . . . . . . . . . . . . 12
AJAR CHIME . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
AMBIENT TEMPERATURE SENSOR . . . . . . . . . 12
AUTO HEADLAMPS . . . . . . . . . . . . . . . . . . . . . 13
COURTESY LAMP SWITCH . . . . . . . . . . . . . . . 12
ENGINE TEMPERATURE CRITICAL CHIME . . . 13
IGNITION SWITCH SENSE . . . . . . . . . . . . . . . . 13
INSTRUMENT PANEL DIMMING . . . . . . . . . . . . 13
DESCRIPTION AND OPERATION
INTRODUCTION
The Body Control Module (BCM) used in this vehi-
cle provides a communication interface with other
controllers and modules. The BCM also controls var-
ious vehicle functions. Circuit operation of specific
systems or components controlled by the BCM are
found in wiring diagram section covering the compo-
nent or system.
This section of the wiring diagrams provides an
overview of the functions controlled or supported by
the BCM. The BCM provides or supports the follow-
ing features:
• A/C Select Switch Status
• Ambient Temperature
• Automatic Funeral Mode
• Automatic Headlamp Control
• Chime
• Courtesy Lamps with Time Out
• Door, Hood or Liftgate Ajar Status
• Door Lock Inhibit
• Electronic Odometer
• Electronic Vehicle Information Center
• Fog Lamp Control
• Headlamp Delay
• High Beam Indicator
• Illuminated Entry
• Instrument Panel Dimming
• Intermittent Wiper Control
• Liftgate Courtesy Lamp Disable
• Mechanical Instrument Cluster
• Rear Window Defogger Control
• Remote Radio Control
• Seat Belt Reminder
• Speed Sensitive Intermittent Wipe Control
• Vehicle Theft Security System
The BCM communicates with the following control-
lers and modules over the CCD bus:
8W - 45 BODY CONTROL MODULE
8W-45 BODY CONTROL MODULE
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INDEX
INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . 12
KEY-IN IGNITION CHIME . . . . . . . . . . . . . . . . . 13
LIFTGATE COURTESY LAMP DISABLE
SWITCH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
LOW FUEL WARNING LAMP ANNOUNCEMENT
CHIME . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
LOW OIL PRESSURE WARNING CHIME . . . . . . 13
PARK LAMP SWITCH SENSE . . . . . . . . . . . . . . 13
SEAT BELT SWITCH . . . . . . . . . . . . . . . . . . . . . 13
• Automatic Temperature Control (ATC) Module
• Compass (Overhead Console)
• Driver Door Module (DDM)
• Mechanical Instrument Cluster
• Memory Seat Module
• Passenger Door Module (PDM)
• Powertrain Control Module
• Vehicle Information Center
• Radio
Circuit A250 from fuse 11 in the Power Distribu-
tion Center (PDC) powers circuit F75 through fuse 7
in the junction block. Circuit F75 supplies battery
voltage to the BCM. Circuits Z1 and Z2 provide
ground for the BCM.
A/C SELECT SWITCH
If the vehicle is equipped with Automatic Temper-
ature Control (ATC), the Automatic Temperature
Control Module sends the A/C select switch to the
Body Control Module (BCM) on circuit C90. If the
vehicle has manual A/C, the A/C-heater control
switch sends the A/C select signal to the BCM on cir-
cuit C90.
AMBIENT TEMPERATURE SENSOR
The ambient air temperature sensor is a variable
resistor. As ambient (outside) temperature varies, the
resistance in the sensor changes. Circuit C8 from the
Body Control Module (BCM) supplies power to the
sensor. Circuit D41 provides the sensor signal to the
BCM.
COURTESY LAMP SWITCH
When the courtesy lamp switch inside the head-
lamp switch closes, it completes a path to ground for
circuit M11 from the Body Control Module (BCM).
The BCM energizes the courtesy lamp relay in the
junction block to power the courtesy lamps. Refer to
section 8W-44.
ZG
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