Description And Operation; Body Control Module - Jeep 1997 Grand Cherokee Service Manual

8F - 2 AUDIO SYSTEMS

DESCRIPTION AND OPERATION

RADIO
Factory-installed receiver
model is affected by the country for which the vehicle
is manufactured. Available factory-installed radio
receivers for vehicles destined for sale in North
America include an AM/FM/cassette (RAS sales
code), an AM/FM/cassette/5-band graphic equalizer
with CD changer control feature (RBN sales code), or
an AM/FM/CD/cassette/3-band
(RAZ sales code).
Available factory-installed radio receivers for vehi-
cles destined for sale outside North America include
an FM/MW/LW/cassette with RDS traffic information
and antitheft features (RBL sales code), an AM/FM/
cassette/5-band graphic equalizer with CD changer
control feature (RBN sales code), an AM/FM/cassette
with CD changer control feature (RBA sales code), or
an AM/FM/cassette with CD changer control feature
(RBJ sales code).
All factory-installed radio receivers are stereo Elec-
tronically Tuned Radios (ETR) and include an elec-
tronic digital clock function.
All factory-installed radio receivers for vehicles
destined for sale in North America, except the RAS
model, communicate on the Chrysler Collision Detec-
tion (CCD) data bus network through a separate two-
way wire harness connector. The CCD data bus
network allows the sharing of sensor information.
This helps to reduce wire harness complexity, inter-
nal controller hardware, and component sensor cur-
rent loads. At the same time, this system provides
increased reliability,
allows the addition of many new feature capabilities.
Radios connected to the CCD data bus network in
vehicles equipped with the optional Vehicle Informa-
tion Center (VIC) have a clock synchronization fea-
ture. The VIC clock display is automatically updated
to the setting shown on the radio clock through a
message sent on the CCD data bus by the radio.
Refer to Group 8E - Instrument Panel Systems for
more information on the VIC module.
In addition, radios connected to the CCD data bus
have several audio system functions that can be diag-
nosed using a DRB scan tool. Refer to the proper
Diagnostic Procedures manual for more information
on DRB testing of the audio systems.
For more information on radio features, setting
procedures, and control functions refer to the owner's
manual in the vehicle glove box.
REMOTE RADIO SWITCH
A remote radio control switch option is available on
Grand Cherokee Limited models sold in North Amer-
ica with the AM/FM/cassette/5-band graphic equal-
availability for
graphic equalizer
enhanced diagnostics,
izer (RBN sales code) with CD changer control
feature, or the AM/FM/CD/cassette/3-band graphic
equalizer (RAZ sales code) radio receivers. Two rock-
er-type switches are mounted on the back (instru-
this
ment panel side) of the steering wheel spokes. The
switch on the left spoke is the seek switch and has
seek up, seek down, and preset station advance func-
tions. The switch on the right spoke is the volume
control switch and has volume up, and volume down
functions.
These switches are resistor multiplexed units that
are hard-wired to the Body Control Module (BCM)
through the clockspring. The BCM sends the proper
messages on the Chrysler Collision Detection (CCD)
data bus network to the radio receiver. For diagnosis
of the BCM or the CCD data bus, refer to the proper
Body Diagnostic Procedures manual. For more infor-
mation on the operation of the remote radio switch
controls, refer to the owner's manual in the vehicle
glove box.

BODY CONTROL MODULE

A Body Control Module (BCM) is used on this
model to control and integrate many of the electronic
functions and features included on the vehicle. The
BCM contains a central processing unit and inter-
faces with other modules in the vehicle on the
Chrysler Collision Detection (CCD) data bus network.
The CCD data bus network allows the sharing of
sensor information. This helps to reduce wire har-
ness complexity, reduce internal controller hardware,
and reduce component sensor current loads. At the
same time, this system provides increased reliability,
enhanced diagnostics, and allows the addition of
and
many new feature capabilities.
One of the functions and features that the BCM
supports and controls, is the remote radio switches
on vehicles so equipped. The BCM receives hard-
wired resistor multiplexed inputs from the remote
radio switches. The programming in the BCM allows
it to process those inputs and send the proper mes-
sages to the radio over the CCD data bus to control
the radio volume, station seek, and preset station
advance functions.
The BCM is mounted under the driver side out-
board end of the instrument panel, behind the instru-
ment panel
outboard switch pod. Refer to Group 8E - Instrument
Panel Systems for the removal and installation pro-
cedures. For diagnosis of the BCM or the CCD data
bus, refer to the proper Body Diagnostic Procedures
manual. The BCM can only be serviced by an autho-
rized electronic repair station. Refer to the latest
Warranty Policies and Procedures manual for a cur-
rent listing of authorized electronic repair stations.
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