General Information; Power Mirror Switch; Power Mirror; Diagnosis And Testing - Jeep 1997 Grand Cherokee Service Manual

8T - 2 POWER MIRROR SYSTEMS
GENERAL INFORMATION (Continued)
enhanced diagnostics, and allows the addition of
many new feature capabilities.
This group covers only the conventional diagnostic
procedures for the power mirror system components.
For diagnosis of the memory system, use of a DRB
scan tool and the proper Body Diagnostic Procedures
manual are recommended. For additional information
on the features and functions of the memory system,
refer to the vehicle owner's manual.
DESCRIPTION AND OPERATION

POWER MIRROR

The power mirrors are connected to battery feed at
all times. Each mirror head contains two electric
motors, two drive mechanisms, an electric heating
element, horizontal and vertical position sensors for
the memory system option, and the mirror glass. One
motor and drive controls mirror up-and-down move-
ment, and the other controls right-and-left move-
ment.
An optional driver side outside electrochromic mir-
ror is able to automatically change its reflectance
level. This mirror is controlled by the circuitry of the
automatic day/night inside rear view mirror. A thin
layer of electrochromic material between two pieces
of conductive glass make up the face of the mirror.
Two photocell sensors on the inside rear view mirror
are used to monitor light levels and adjust the reflec-
tance of both the inside and driver side outside mir-
rors. This change in reflectance helps to reduce the
glare of headlamps approaching the vehicle from the
rear. Refer to the Automatic Day/Night Mirror sec-
tion of this group for more information on the opera-
tion of this system.
The power mirror assembly cannot be repaired.
Only the mirror glass and glass case are serviced
separately. If any other component of the power mir-
ror unit is faulty or damaged, the entire assembly
must be replaced.

POWER MIRROR SWITCH

Both the right and left power outside mirrors are
controlled by a single multi-function switch unit
located on the driver side door trim panel. This
switch unit is integral to the Driver Door Module
(DDM).
A selector switch is moved right (right mirror con-
trol), left (left mirror control), or center to turn the
power outside mirror control off. Then one of four
directional control buttons is depressed to control
movement of the selected mirror up, down, right, or
left.
The power mirror switch cannot be repaired and, if
faulty or damaged, the DDM unit must be replaced.
DOOR MODULE
A Driver Door Module (DDM) and a Passenger
Door Module (PDM) are used on this model to control
and integrate many of the electronic features and
functions on the vehicle. The DDM and PDM commu-
nicate with each other, and with other vehicle mod-
ules 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, internal controller hardware, and
component sensor current loads. At the same time,
this system provides increased reliability, enhanced
diagnostics, and allows the addition of many new fea-
ture capabilities.
Each door module controls the positioning of its
respective outside mirror. When the power mirror
switch on the DDM is used to position the passenger
side outside mirror, the DDM sends mirror position-
ing messages to the PDM on the CCD data bus. The
PDM then moves the passenger side mirror accord-
ingly.
Both the PDM and DDM respond to the defogger
switch status messages sent by the Body Control
Module (BCM) on the CCD data bus to control the
heater elements of their respective mirrors. Refer to
Group 8N - Electrically Heated Systems for more
information on this feature.
On models equipped with the optional memory sys-
tem, each door module stores the Driver 1 and 2 mir-
ror position information for its respective mirror.
When the DDM receives a Driver 1 or 2 signal from
the Memory Switch or from the Remote Keyless
Entry (RKE) receiver in the PDM, the DDM positions
the driver side mirror and sends a memory recall
message back to the PDM on the CCD data bus to
position the passenger side mirror.
For diagnosis of the DDM, PDM, or the CCD data
bus network, refer to the proper Body Diagnostic
Procedures manual.

DIAGNOSIS AND TESTING

POWER MIRROR SYSTEM

If only one power mirror is inoperative, or partially
inoperative, see the tests under Power Mirror in this
group. If both power mirrors are inoperative, proceed
as follows. For circuit descriptions and diagrams,
refer to 8W-62 - Power Mirrors in Group 8W - Wiring
Diagrams.
NOTE: The following tests may not prove conclu-
sive in the diagnosis of this system. The most reli-
able, efficient, and accurate means to diagnose this
system involves the use of a DRB scan tool and the
proper Body Diagnostic Procedures Manual.
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