Body Control Module; Intermittent Wipe Relay - Jeep 1996 Grand Cherokee Service Manual

ZJ
DESCRIPTION AND OPERATION (Continued)
secure the unit to the liftgate outer panel. The rear
wiper arm is mounted directly to the motor output
shaft. The rear wiper motor unit contains integral
electronic controls that provide the following operat-
ing modes:
• Intermittent wipe with a five to eight second
delay between sweeps.
• Continuous fixed-cycle wipe.
• A park mode that operates the wiper motor until
the blade reaches its park position when the rear
wiper switch or ignition switch is placed in the Off
position, or when the liftgate or liftglass (if equipped)
is opened.
• A rear washer mode that provides two or three
wiper blade sweeps before returning to the previously
selected rear wiper switch mode.
The rear wiper motor cannot be repaired. If faulty,
the entire wiper motor assembly must be replaced.
WIPER AND WASHER SWITCHES
FRONT
The front wiper and washer switches are contained
in the multi-function switch assembly. The multi-
function switch assembly is mounted to the left side
of the steering column. This switch contains circuitry
for the following functions:
• Turn signals
• Hazard warning
• Headlamp beam selection
• Headlamp optical horn
• Windshield wipers
• Windshield washers.
The information contained in this group addresses
only the switch functions for the wiper and washer
systems. For information relative to the other switch
functions, refer to the appropriate group. However,
the multi-function switch cannot be repaired. If any
function of the switch is faulty, the entire switch
assembly must be replaced.
REAR
The single two-function rear wiper switch is part of
the right switch pod unit, which is located on the
instrument panel just right of the steering column.
The rear wiper switch controls the rear wiper and
washer functions. The sliding-type switch features a
detent in the On and Delay positions. The switch
knob is depressed to actuate the rear washer switch,
and activate the rear washer system. Both the rear
wiper and rear washer motors will operate continu-
ously for as long as the switch is held in the momen-
tary Wash position. The rear wiper switch cannot be
repaired and, if faulty, the right switch pod unit must
be replaced.
WIPER AND WASHER SYSTEMS
Fig. 1 Multi-Function Switch

BODY CONTROL MODULE

A Body Control Module (BCM) is used on this
model to control and integrate many of the vehicle's
electrical functions and features. The BCM contains
a central processing unit and interfaces 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 wiring 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
many new feature capabilities.
Some of the functions and features that the BCM
supports and controls are the speed sensitive inter-
mittent wipe, pulse wipe, and wipe-after-wash
modes. The BCM is programmed to energize the
intermittent wipe relay in response to certain inputs
from the multi-function switch and the wiper motor
park switch. For the speed sensitive intermittent
wipe feature, the BCM also uses an input from the
vehicle speed sensor, which is received on the CCD
data bus from the Powertrain Control Module (PCM).
The BCM is mounted under the left end of the
instrument panel, behind the instrument panel sup-
port armature and below the left switch pod. Refer to
Group 8E - Instrument Panel Systems for removal
and installation procedures. 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 authorized repair station. Refer to the
Warranty Policies and Procedures Manual for a list-
ing of authorized repair stations.

INTERMITTENT WIPE RELAY

The intermittent wipe relay is a International
Standards Organization (ISO) micro-relay. The termi-
nal designations and functions are the same as a con-
8K - 3