
AUTOMATIC DAY / NIGHT
MIRROR
DESCRIPTION
An automatic dimming inside day/night rear view
mirror and an automatic dimming driver side outside
rear view mirror are available factory-installed
options on this model. Following is a general descrip-
tion of this optional equipment.
The automatic day/night mirror is able to automat-
ically change its reflectance. A thin layer of electro-
chromic material between two pieces of conductive
glass make up the face of the mirror. Two photocell
sensors are used to monitor light levels and adjust
the reflectance of the mirror to reduce the glare of
headlamps approaching the vehicle from the rear.
For removal procedures, (Refer to 23 - BODY/IN-
TERIOR/REAR VIEW MIRROR - REMOVAL).
OPERATION
The ambient photocell sensor faces forward, to
detect the outside light levels. A second sensor faces
rearward to detect the light level received through
the vehicles back window. When the difference
between the two light levels becomes too great (the
light level received at the rear of the mirror is much
higher than that at the front of the mirror), the mir-
ror begins to darken.
The mirror switch allows the driver a manual con-
trol of whether the automatic dimming feature is
operational. When AUTO is selected a small Light-
Emitting Diode (LED), to the right of the mirror
switch, is illuminated. The automatic dimming fea-
ture will only operate when the ignition switch is in
the On position. The mirror also senses the backup
lamp circuit, and will automatically disable its self-
dimming feature whenever the transmission gear
selector is in the Reverse position.
NOTE: The mirror always defaults to an ON state
upon ignition.
The driver side automatic dimming mirror is stan-
dard with the automatic dimming inside mirror. The
signal to control the dimming of that mirror is gen-
erated by the automatic day/night inside rear view
mirror circuitry. That signal is then delivered to the
driver side outside rear view mirror on a hard wired
circuit.
The automatic day/night mirror cannot be
repaired. If faulty or damaged, the entire inside rear
view mirror assembly must be replaced.
DIAGNOSIS AND TESTING
AUTOMATIC DAY / NIGHT MIRROR
For circuit descriptions and diagrams, refer to the
appropriate wiring information. The wiring informa-
tion includes wiring diagrams, proper wire and con-
nector repair procedures, details of wire harness
routing and retention, connector pin-out information
and location views for the various wire harness con-
nectors, splices and grounds.
(1) Check the fuse in the intelligent power module.
If OK, go to Step 2. If not OK, repair the shorted cir-
cuit or component as required and replace the faulty
fuse.
(2) Turn the ignition switch to the On position.
Check for battery voltage at the fuse in the intelli-
gent power module. If OK, go to Step 3. If not OK,
repair the open circuit to the ignition switch as
required.
(3) Unplug the wire harness connector from the
automatic day/night mirror. Check for battery voltage
at the fused ignition switch output circuit cavity of
the automatic day/night mirror wire harness connec-
tor. If OK, go to Step 4. If not OK, repair the open
circuit to the junction block as required.
(4) Turn the ignition switch to the Off position.
Check for continuity between the ground circuit cav-
ity of the automatic day/night mirror wire harness
connector and a good ground. There should be conti-
nuity. If OK, go to Step 5. If not OK, repair the cir-
cuit to ground as required.
(5) Turn the ignition switch to the On position. Set
the parking brake. Place the transmission gear selec-
tor lever in the Reverse position. Check for battery
voltage at the backup lamp switch output circuit cav-
ity of the automatic day/night mirror wire harness
connector. If voltage is present, reinstall the auto-
matic day/night mirror wire harness connector and
go to Step 6. If not OK, repair the open circuit as
required.
(6) Place the transmission gear selector lever in
the Neutral position. Place the automatic day/night
mirror switch in the On (LED in the switch is
lighted) position. Cover the forward facing ambient
photocell sensor to keep out any ambient light.
NOTE: The ambient photocell sensor must be cov-
ered completely, so that no light reaches the sen-
sor. Use a finger pressed tightly against the sensor,
or cover the sensor completely with electrical tape.
(7) Shine a light into the rearward facing head-
lamp photocell sensor. The automatic day/night mir-
ror should darken. The automatic day/night mirror
should darken within 2 minutes if testing for the
first time. For immediate response, turn the vehicle
8N - 28 POWER MIRRORSRS

The ORC is secured with screws to a stamped steel
mounting bracket welded onto the top of the floor
panel transmission tunnel just behind and under-
neath the instrument panel center stack in the pas-
senger compartment of the vehicle (Fig. 38).
Concealed within a hollow in the center of the die
cast aluminum ORC housing is the electronic cir-
cuitry of the ORC which includes a microprocessor,
an electronic impact sensor, an electronic safing sen-
sor, and an energy storage capacitor. A stamped
metal cover plate is secured to the bottom of the
ORC housing with four screws to enclose and protect
the internal electronic circuitry and components.
An arrow printed on the label on the top of the
ORC housing provides a visual verification of the
proper orientation of the unit, and should always be
pointed toward the front of the vehicle. The ORC
housing has integral mounting flanges. the ORC has
two molded plastic electrical connectors that exits the
right facing side of the ORC housing. These terminal
pins connect the ORC to the vehicle electrical system.
The impact sensor and safing sensor internal to
the ORC are calibrated for the specific vehicle, and
are only serviced as a unit with the ORC. In addi-
tion, there are unique versions of the ORC for vehi-
cles with or without curtain airbags. The ORC cannot
be repaired or adjusted and, if damaged or faulty, it
must be replaced.
OPERATION
The microprocessor in the Occupant Restraint Con-
troller (ORC) contains the supplemental restraint
system logic circuits and controls all of the supple-
mental restraint system components. The ORC uses
On-Board Diagnostics (OBD) and can communicatewith other electronic modules in the vehicle as well
as with the diagnostic scan tool using the Program-
mable Communication Interface (PCI) data bus. This
method of communication is used for control of the
airbag indicator in the ElectroMechanical Instrument
Cluster (EMIC) and for supplemental restraint sys-
tem diagnosis and testing through the 16-way Data
Link Connector (DLC) located on the driver side
lower edge of the instrument panel.
The ORC microprocessor continuously monitors all
of the supplemental restraint system electrical cir-
cuits to determine the system readiness. If the ORC
detects a monitored system fault, it sets an active
and stored Diagnostic Trouble Code (DTC) and sends
electronic messages to the EMIC over the PCI data
bus to turn on the airbag indicator. An active fault
only remains for the duration of the fault, or in some
cases for the duration of the current ignition switch
cycle, while a stored fault causes a DTC to be stored
in memory by the ORC. For some DTC's, if a fault
does not recur for a number of ignition cycles, the
ORC will automatically erase the stored DTC. For
other internal faults, the stored DTC is latched for-
ever.
On models equipped with the Occupant Classifica-
tion System (OCS), the ORC communicates with the
Occupant Classification Module (OCM) over the PCI
data bus. The ORC will internally disable the pas-
senger airbag and seat belt tensioner deployment cir-
cuits if the OCM detects that the passenger side
front seat is unoccupied or that it is occupied by a
load that is inappropriate for an airbag deployment.
The ORC also provides a control output to the Pas-
senger Airbag Disabled (PAD) indicator through the
passenger airbag indicator driver circuit. The OCM
notifies the ORC when it has detected a monitored
system fault and stored a DTC in its memory for any
faulty OCS component or circuit, then the ORC sets
a DTC and controls the airbag indicator operation
accordingly.
The ORC receives battery current through two cir-
cuits; a fused ignition switch output (RUN) circuit
through a fuse in the Junction Block (JB), and a
fused ignition switch output (RUN/START) circuit
through a second fuse in the JB. The ORC receives
ground through a ground circuit of the instrument
panel wire harness. These connections allow the ORC
to be operational whenever the ignition switch is in
the START or ON positions.
The ORC also contains an energy-storage capacitor.
When the ignition switch is in the START or ON
positions, this capacitor is continually being charged
with enough electrical energy to deploy the front sup-
plemental restraint components for up to one second
following a battery disconnect or failure. The purpose
of the capacitor is to provide backup supplemental
Fig. 38 ORC LOCATION
1 - ORC ELECTRICAL CONNECTORS
2 - ORC
3 - ORC MOUNTING SCREWS
8O - 28 RESTRAINTSRS
OCCUPANT RESTRAINT CONTROLLER (Continued)