2005 MERCEDES-BENZ SPRINTER Service Repair Manual

Refer to the appropriate wiring information for
additional details.
GROUNDS
The EMIC receives and supplies a ground path to
several switches and sensors through the following
hard wired circuits:
NOTE: Final approved circuit names were not yet
available at the time this information was compiled.
²Ambient Temperature Sensor Return
(Optional)
²Fuel Level Sensor Return
²Ground
Refer to the appropriate wiring information for
additional details.
COMMUNICATION
The EMIC has provisions for the following commu-
nication circuits:
NOTE: Final approved circuit names were not yet
available at the time this information was compiled.
²CAN Data Bus - High
²CAN Data Bus - Low
²Diagnostic Serial Communication Interface
(SCI) Data Bus Line
Refer to the appropriate wiring information for
additional details.
DIAGNOSIS AND TESTING - INSTRUMENT
CLUSTER
The hard wired inputs to and outputs from the
instrument cluster may be diagnosed and tested
using conventional diagnostic tools and procedures.
Refer to the appropriate wiring information. The wir-
ing information includes wiring diagrams, proper
wire and connector repair procedures, details of wire
harness routing and retention, connector pin-out
information and location views for the various wire
harness connectors, splices and grounds.
If the instrument cluster is completely inoperative,
be certain to check the fused B(+) circuit fuses and
wiring for the instrument cluster. If the cluster gen-
eral illumination is inoperative, be certain to check
the instrument lighting fuse and the input circuit to
the instrument cluster from the exterior lighting cir-
cuitry of the multi-function switch on the steering
column.
Conventional diagnostic methods may not prove
conclusive in the diagnosis of the instrument cluster.
In order to obtain conclusive testing of the instru-
ment cluster, the Controller Area Network (CAN)
data bus network and all of the electronic modules
that provide inputs to or receive outputs from theinstrument cluster must also be checked. The most
reliable, efficient, and accurate means to diagnose
the instrument cluster, the CAN data bus network,
and the electronic modules that provide inputs to or
receive outputs from the instrument cluster requires
the use of a DRBIIItscan tool and the appropriate
diagnostic information. The DRBIIItscan tool can
provide confirmation that the CAN data bus network
is functional, that all of the modules are sending and
receiving the proper electronic messages over the
CAN data bus, and that the instrument cluster is
receiving the proper hard wired inputs and respond-
ing with the proper hard wired outputs needed to
perform its many functions.
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE SUPPLEMENTAL RESTRAINT
SYSTEM BEFORE ATTEMPTING ANY STEERING
WHEEL, STEERING COLUMN, DRIVER AIRBAG,
PASSENGER AIRBAG, SEAT BELT TENSIONER, OR
INSTRUMENT PANEL COMPONENT DIAGNOSIS OR
SERVICE. DISCONNECT AND ISOLATE THE BAT-
TERY NEGATIVE (GROUND) CABLE, THEN WAIT
TWO MINUTES FOR THE SYSTEM CAPACITOR TO
DISCHARGE BEFORE PERFORMING FURTHER
DIAGNOSIS OR SERVICE. THIS IS THE ONLY SURE
WAY TO DISABLE THE SUPPLEMENTAL
RESTRAINT SYSTEM. FAILURE TO TAKE THE
PROPER PRECAUTIONS COULD RESULT IN ACCI-
DENTAL SUPPLEMENTAL RESTRAINT DEPLOY-
MENT AND POSSIBLE PERSONAL INJURY.
REMOVAL
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE SUPPLEMENTAL RESTRAINT
SYSTEM BEFORE ATTEMPTING ANY STEERING
WHEEL, STEERING COLUMN, DRIVER AIRBAG,
PASSENGER AIRBAG, SEAT BELT TENSIONER, OR
INSTRUMENT PANEL COMPONENT DIAGNOSIS OR
SERVICE. DISCONNECT AND ISOLATE THE BAT-
TERY NEGATIVE (GROUND) CABLE, THEN WAIT
TWO MINUTES FOR THE SYSTEM CAPACITOR TO
DISCHARGE BEFORE PERFORMING FURTHER
DIAGNOSIS OR SERVICE. THIS IS THE ONLY SURE
WAY TO DISABLE THE SUPPLEMENTAL
RESTRAINT SYSTEM. FAILURE TO TAKE THE
PROPER PRECAUTIONS COULD RESULT IN ACCI-
DENTAL SUPPLEMENTAL RESTRAINT DEPLOY-
MENT AND POSSIBLE PERSONAL INJURY.
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the cluster bezel from the instrument
panel. (Refer to 23 - BODY/INSTRUMENT PANEL/
CLUSTER BEZEL - REMOVAL).
VAINSTRUMENT CLUSTER 8J - 7
INSTRUMENT CLUSTER (Continued)

(3) Remove the cluster top cover from the instru-
ment panel. (Refer to 23 - BODY/INSTRUMENT
PANEL/TOP COVER - CLUSTER - REMOVAL).
(4) Remove the two screws that secure the instru-
ment cluster mounting ears to the instrument panel
base structure (Fig. 4).
(5) Roll the top of the instrument cluster rearward
far enough to access and release the latch that
secures the RKE/immobilizer module to the back of
the instrument cluster rear cover and disengage the
module from the cluster (Fig. 5).
(6) Depress the release (Arrow A) and lift the lever
arm (Arrow B) to disconnect each of the two frame
wire harness connectors for the cluster from the con-
nector receptacles on the back of the cluster housing
(Fig. 6).
(7) Lift the instrument cluster upward far enough
to disengage the two molded plastic pivot loops inte-
gral to the base of the cluster hood from the two
pairs of molded plastic pivot hooks that are integral
to the top of the instrument panel base structure.
(8) Remove the instrument cluster from the instru-
ment panel.
Fig. 4 Instrument Cluster Remove/Install
1 - SCREW (2)
2 - COVER
3 - SCREW (2)
4 - INSTRUMENT CLUSTER
5 - LOOP (2)
Fig. 5 RKE/Immobilizer Module
1 - RKE/IMMOBILIZER MODULE
2-LATCH
3 - INSTRUMENT CLUSTER
Fig. 6 Cluster Connectors
1 - STEERING WHEEL
2 - INSTRUMENT CLUSTER
3 - CONNECTOR (2)
8J - 8 INSTRUMENT CLUSTERVA
INSTRUMENT CLUSTER (Continued)

INSTALLATION
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE SUPPLEMENTAL RESTRAINT
SYSTEM BEFORE ATTEMPTING ANY STEERING
WHEEL, STEERING COLUMN, DRIVER AIRBAG,
PASSENGER AIRBAG, SEAT BELT TENSIONER, OR
INSTRUMENT PANEL COMPONENT DIAGNOSIS OR
SERVICE. DISCONNECT AND ISOLATE THE BAT-
TERY NEGATIVE (GROUND) CABLE, THEN WAIT
TWO MINUTES FOR THE SYSTEM CAPACITOR TO
DISCHARGE BEFORE PERFORMING FURTHER
DIAGNOSIS OR SERVICE. THIS IS THE ONLY SURE
WAY TO DISABLE THE SUPPLEMENTAL
RESTRAINT SYSTEM. FAILURE TO TAKE THE
PROPER PRECAUTIONS COULD RESULT IN ACCI-
DENTAL SUPPLEMENTAL RESTRAINT DEPLOY-
MENT AND POSSIBLE PERSONAL INJURY.
(1) Position the instrument cluster to the instru-
ment panel.
(2) Align the two molded plastic pivot loops inte-
gral to the base of the cluster hood between the two
pairs of molded plastic pivot hooks that are integral
to the top of instrument panel base structure, then
push downward on the top of the cluster until the
loops snap into engagement with the hooks (Fig. 6).
(3) Roll the top of the instrument cluster rearward
to access, reconnect, and latch the two frame wire
harness connectors for the cluster to the connector
receptacles on the back of the cluster housing.
(4) Engage and latch the RKE/immobilizer module
to the back of the instrument cluster rear cover (Fig.
5)
(5) Roll the top of the instrument cluster forward
to position the instrument cluster into the instru-
ment panel.
(6) Install and tighten the two screws that secure
the instrument cluster mounting ears to the instru-
ment panel base structure (Fig. 4). Tighten the
screws to 2 N´m (20 in. lbs.).
(7) Reinstall the cluster top cover onto the instru-
ment panel. (Refer to 23 - BODY/INSTRUMENT
PANEL/TOP COVER - CLUSTER - INSTALLA-
TION).
(8) Reinstall the cluster bezel onto the instrument
panel. (Refer to 23 - BODY/INSTRUMENT PANEL/
CLUSTER BEZEL - INSTALLATION).
(9) Reconnect the battery negative cable.
ABS INDICATOR
DESCRIPTION
An Anti-lock Brake System (ABS) indicator is stan-
dard equipment on all instrument clusters. The ABS
indicator is located near the lower edge of the instru-
ment cluster, to the right of the multi-function indi-
cator display. The ABS indicator consists of the
International Control and Display Symbol icon for
ªFailure of Anti-lock Braking Systemº imprinted
within a rectangular cutout in the opaque layer of
the instrument cluster overlay. The dark outer layer
of the overlay prevents the indicator from being
clearly visible when it is not illuminated. An amber
Light Emitting Diode (LED) behind the cutout in the
opaque layer of the overlay causes the icon to appear
silhouetted against an amber field through the trans-
lucent outer layer of the overlay when the indicator
is illuminated from behind by the LED, which is sol-
dered onto the instrument cluster electronic circuit
board. The ABS indicator is serviced as a unit with
the instrument cluster.
OPERATION
The ABS indicator gives an indication to the vehi-
cle operator when the ABS or the electronic brake
force distribution (EBV) systems are faulty or inoper-
ative. This indicator is controlled by a transistor on
the instrument cluster circuit board based upon clus-
ter programming and electronic messages received by
the cluster from the Controller Antilock Brake (CAB)
over the Controller Area Network (CAN) data bus.
The ABS indicator Light Emitting Diode (LED) is
completely controlled by the instrument cluster logic
circuit, and that logic will only allow this indicator to
operate when the instrument cluster detects that the
ignition switch is in the On position. Therefore, the
LED will always be off when the ignition switch is in
any position except On. The LED only illuminates
when it is provided a path to ground by the instru-
ment cluster transistor. The instrument cluster will
turn on the ABS indicator for the following reasons:
²Bulb Test- Each time the ignition switch is
turned to the On position the ABS indicator is illu-
minated by the cluster for about two seconds as a
bulb test.
VAINSTRUMENT CLUSTER 8J - 9
INSTRUMENT CLUSTER (Continued)

²ABS Lamp-On Message- Each time the clus-
ter receives a lamp-on message from the CAB, the
ABS indicator will be illuminated. The indicator
remains illuminated until the cluster receives a
lamp-off message from the CAB, or until the ignition
switch is turned to the Off position, whichever occurs
first.
The CAB continually monitors the ABS and EBV
circuits and sensors to decide whether the systems
are in good operating condition. The CAB then sends
the proper lamp-on or lamp-off messages to the
instrument cluster. If the CAB sends a lamp-on mes-
sage after the bulb test, it indicates that the CAB
has detected a system malfunction and/or that the
ABS or EBV systems have become inoperative. The
CAB will store a Diagnostic Trouble Code (DTC) for
any malfunction it detects. For proper diagnosis of
the ABS and EBV systems, the CAB, the CAN data
bus, the electronic message inputs to the instrument
cluster, or the instrument cluster circuitry that con-
trols the ABS indicator, a DRBIIItscan tool is
required. Refer to the appropriate diagnostic infor-
mation.
AIRBAG INDICATOR
DESCRIPTION
An airbag indicator is standard equipment on all
instrument clusters. The airbag indicator is located
near the left edge of the instrument cluster, next to
the tachometer. The airbag indicator consists of a
stencil-like cutout of the letters ªSRSº in the opaque
layer of the instrument cluster overlay. The dark
outer layer of the overlay prevents the indicator from
being clearly visible when it is not illuminated. A red
Light Emitting Diode (LED) behind the cutout in the
opaque layer of the overlay causes the ªSRSº text to
appear in red through the translucent outer layer of
the overlay when the indicator is illuminated from
behind by the LED, which is soldered onto the
instrument cluster electronic circuit board. The air-
bag indicator is serviced as a unit with the instru-
ment cluster.
OPERATION
The airbag (SRS) indicator gives an indication to
the vehicle operator when the Airbag Control Module
(ACM) has recorded a Diagnostic Trouble Code (DTC)
for a Supplemental Restraint System (SRS) circuit or
component malfunction. Such a DTC may indicate
that the SRS is faulty or inoperative. The airbag
indicator is controlled by a transistor on the instru-
ment cluster circuit board based upon cluster pro-
gramming and a hard wired input received by the
cluster from the ACM. The airbag indicator LightEmitting Diode (LED) is completely controlled by the
instrument cluster logic circuit, and that logic will
only allow this indicator to operate when the instru-
ment cluster detects that the ignition switch is in the
On position. Therefore, the LED will always be off
when the ignition switch is in any position except
On. The LED only illuminates when it is provided a
path to ground by the instrument cluster transistor.
The instrument cluster will turn on the airbag indi-
cator for the following reasons:
²Bulb Test- Each time the ignition switch is
turned to the On position the airbag indicator is illu-
minated for about four seconds. The entire four sec-
ond bulb test is a function of the ACM.
²Airbag Lamp-On Input- Each time the cluster
receives a lamp-on input from the ACM, the airbag
indicator will be illuminated. The indicator can be
flashed on and off, or illuminated solid, as dictated
by the ACM input. For some DTC's, if the problem
does not recur, the ACM will send a lamp-off input
automatically. Other DTC's may require that a fault
be repaired and the ACM be reset before a lamp-off
input will be sent. For more information on the ACM
and the DTC set and reset parameters, refer to 8 -
ELECTRICAL/RESTRAINTS/AIRBAG CONTROL
MODULE - OPERATION). The indicator remains
illuminated until the cluster receives a lamp-off
input from the ACM, or until the ignition switch is
turned to the Off position, whichever occurs first.
²Airbag Indicator Malfunction- Following the
seatbelt reminder function, each time the cluster
detects a malfunction in the airbag (SRS) indicator or
the airbag indicator circuit, the cluster will flash the
seatbelt indicator on and off. The cluster will con-
tinue to flash the seatbelt indicator until the airbag
indicator circuit fault is resolved, or until the ignition
switch is turned to the Off position, whichever occurs
first.
The ACM continually monitors the SRS circuits
and sensors to decide whether the system is in good
operating condition. The ACM then provides the
proper lamp-on or lamp-off inputs to the instrument
cluster. If the ACM provides a lamp-on input after
the bulb test, it indicates that the ACM has detected
a system malfunction and/or that the airbags and
seat belt tensioners may not deploy when required,
or may deploy when not required. The ACM will
store a DTC for any malfunction it detects. The ACM
input circuit to the instrument cluster can be diag-
nosed using conventional diagnostic tools and meth-
ods. For proper diagnosis of the SRS, the ACM, or
the instrument cluster circuitry that controls the air-
bag indicator, a DRBIIItscan tool is required. Refer
to the appropriate diagnostic information.
8J - 10 INSTRUMENT CLUSTERVA
ABS INDICATOR (Continued)

AMBIENT TEMPERATURE
INDICATOR
DESCRIPTION
An ambient temperature indicator is optional
equipment on all instrument clusters. In vehicles so
equipped, the ambient temperature indication can be
toggled with the clock indication on the right side of
the multi-function indicator Liquid Crystal Display
(LCD) located near the lower edge of the instrument
cluster, directly below the speedometer. The ambient
temperature indication consists of a numeric value
with a ª+º (plus) or ª2º (minus) prefix, and the unit
of measure is identified with the characters ªÉCº
(Canadian vehicles only) or ªÉFº (United States vehi-
cles only) located directly above the temperature
indication. The indications of the ambient tempera-
ture indicator are not visible when the LCD is not
illuminated. When illuminated the indications
appear as dark characters and icons silhouetted
against an amber field. When the exterior lighting is
turned Off, the display is illuminated at maximum
brightness. When the exterior lighting is turned On
the display illumination level can be adjusted in con-
cert with the cluster general illumination lighting
using the ª+º (plus) and ª2º (minus) multi-function
indicator push buttons. The ambient temperature
indicator is serviced as a unit with the instrument
cluster.
OPERATION
The optional ambient temperature indicator gives
an indication to the vehicle operator of the outside
air temperature. This indicator is controlled by the
instrument cluster microprocessor based upon cluster
programming and a hard wired input received by the
cluster from the ambient temperature sensor. The
ambient temperature indicator is completely con-
trolled by the instrument cluster logic circuit, and
that logic will allow this indicator to operate when-
ever the multi-function indicator Liquid Crystal Dis-
play (LCD) is activated. Therefore, the ambient
temperature indicator remains functional regardless
of the ignition switch position.
The vehicle operator can choose to have the ambi-
ent temperature indicator displayed instead of the
clock information, but the clock and ambient temper-
ature indicator cannot be displayed at the same time.
The clock or ambient temperature indicator display
option is selected using the multi-function indicator
clock switch on the instrument cluster circuit board.
This switch is actuated manually by depressing the
clock switch push button that extends through the
lower edge of the cluster lens below the left end of
the multi-function indicator. Actuating this switchmomentarily will toggle the display between the
clock and ambient temperature indicator modes.
Actuating this switch twice within about one second
will cause the display to toggle, but then automati-
cally revert to the originally selected mode after
about twenty seconds.
The ambient temperature sensor located below the
front bumper is a Negative Temperature Coefficient
(NTC) thermistor. The internal resistance of the sen-
sor is reduced as the ambient temperature rises. The
instrument cluster continually monitors the resis-
tance through the sensor to determine the tempera-
ture value to be displayed. The current value is
displayed immediately after the LCD is activated.
The display value will remain static regardless of
decreases in the sensor resistance (temperature ris-
ing) below vehicle speeds of 10 to 15 kilometers-per-
hour (6 to 9 miles-per-hour). Decreases in the sensor
resistance above 15 kilometers-per-hour (9 miles-per-
hour) and increases the sensor resistance (tempera-
ture falling) regardless of vehicle speed are displayed
subject to a sixty second delay.
The ambient temperature sensor is connected to
the instrument cluster in series between the ambient
temperature sensor return and sense circuits. The
ambient temperature sensor and the return and
sense circuits to the instrument cluster can be diag-
nosed using conventional diagnostic tools and meth-
ods. For proper diagnosis of the instrument cluster
circuitry that controls the ambient temperature indi-
cator, a DRBIIItscan tool is required. Refer to the
appropriate diagnostic information.
BRAKE/PARK BRAKE
INDICATOR
DESCRIPTION
A brake indicator is standard equipment on all
instrument clusters. The brake indicator is located
near the lower edge of the instrument cluster, to the
left of the multi-function indicator display. In vehi-
cles built for the United States market, the brake
indicator consists of stencil-like cutout of the word
ªBRAKEº in the opaque layer of the instrument clus-
ter overlay. In vehicles built for the Canadian mar-
ket, the brake indicator consists of the International
Control and Display Symbol icon for ªBrake Failureº
imprinted within a rectangular cutout in the opaque
layer of the instrument cluster overlay. In either
case, the dark outer layer of the overlay prevents the
indicator from being clearly visible when it is not
illuminated. A red Light Emitting Diode (LED)
behind the cutout in the opaque layer of the overlay
causes the ªBRAKEº text to appear in red, or the
icon to appear silhouetted against a red field through
VAINSTRUMENT CLUSTER 8J - 11

the translucent outer layer of the overlay when the
indicator is illuminated from behind by the LED,
which is soldered onto the instrument cluster elec-
tronic circuit board. The brake indicator is serviced
as a unit with the instrument cluster.
OPERATION
The brake indicator gives an indication to the vehi-
cle operator when the parking brake is applied, or
when there are certain brake hydraulic system mal-
functions as indicated by a low brake hydraulic fluid
level condition. This indicator is controlled by a tran-
sistor on the instrument cluster circuit board based
upon cluster programming and hard wired inputs
from the park brake switch and the brake fluid level
switch. The brake indicator Light Emitting Diode
(LED) is completely controlled by the instrument
cluster logic circuit, and that logic will only allow
this indicator to operate when the instrument cluster
detects that the ignition switch is in the On position.
Therefore, the LED will always be off when the igni-
tion switch is in any position except On. The LED
only illuminates when it is provided a path to ground
by the instrument cluster transistor. The instrument
cluster will turn on the brake indicator for the follow-
ing reasons:
²Bulb Test- Each time the ignition switch is
turned to the On position the brake indicator is illu-
minated by the instrument cluster for about two sec-
onds as a bulb test.
²Brake Fluid Level Switch Input- Each time
the cluster detects ground on the park brake/brake
fluid level switch sense circuit (brake fluid level
switch closed = brake fluid level low) while the igni-
tion switch is in the On position, the brake indicator
is illuminated. The indicator remains illuminated
until the brake fluid level switch sense input to the
cluster is an open circuit (brake fluid level switch
open = brake fluid level okay), or until the ignition
switch is turned to the Off position, whichever occurs
first.
²Park Brake Switch Input- Each time the
cluster detects ground on the park brake/brake fluid
level switch sense circuit (park brake switch closed =
park brake applied or not fully released) while the
ignition switch is in the On position, the brake indi-
cator is illuminated. The indicator remains illumi-
nated until the park brake switch sense input to the
cluster is an open circuit (park brake switch open =
park brake fully released), or until the ignition
switch is turned to the Off position, whichever occurs
first.
The park brake switch on the park brake pedal
mechanism and the brake fluid level switch in the
brake master cylinder provide a hard wired ground
input to the instrument cluster circuitry through thepark brake/brake fluid level switch sense circuit
whenever the park brake is applied or not fully
released, or whenever the fluid level in the brake
master cylinder is low. The two switches are con-
nected in parallel between ground and the instru-
ment cluster. The park brake switch, brake fluid
level switch, and their input circuit to the instrument
cluster can be diagnosed using conventional diagnos-
tic tools and methods. For proper diagnosis of the
instrument cluster circuitry that controls the brake
indicator, a DRBIIItscan tool is required. Refer to
the appropriate diagnostic information.
BRAKE WEAR INDICATOR
DESCRIPTION
A brake wear indicator is standard equipment on
all instrument clusters. The brake wear indicator is
located near the lower edge of the instrument cluster,
to the left of the multi-function indicator display. The
brake wear indicator consists of the International
Control and Display Symbol icon for ªWorn Brake
Liningsº imprinted within a rectangular cutout in the
opaque layer of the instrument cluster overlay. The
dark outer layer of the overlay prevents the indicator
from being clearly visible when it is not illuminated.
An amber Light Emitting Diode (LED) behind the
cutout in the opaque layer of the overlay causes the
icon to appear silhouetted against an amber field
through the translucent outer layer of the overlay
when the indicator is illuminated from behind by the
LED, which is soldered onto the instrument cluster
electronic circuit board. The brake wear indicator is
serviced as a unit with the instrument cluster.
OPERATION
The brake wear indicator gives an indication to the
vehicle operator when the brake linings have reached
their wear limits. This indicator is controlled by a
transistor on the instrument cluster circuit board
based upon cluster programming and a hard wired
input from the four brake wear sensors, one at each
wheel. The brake wear indicator Light Emitting
Diode (LED) is completely controlled by the instru-
ment cluster logic circuit, and that logic will only
allow this indicator to operate when the instrument
cluster detects that the ignition switch is in the On
position. Therefore, the LED will always be off when
the ignition switch is in any position except On. The
LED only illuminates when it is provided a path to
ground by the instrument cluster transistor. The
instrument cluster will turn on the brake wear indi-
cator for the following reasons:
²Bulb Test- Each time the ignition switch is
turned to the On position the brake wear indicator is
8J - 12 INSTRUMENT CLUSTERVA
BRAKE/PARK BRAKE INDICATOR (Continued)

illuminated by the instrument cluster for about two
seconds as a bulb test.
²Brake Wear Sensor Input- Each time the
cluster detects ground on the brake wear sense cir-
cuit (brake wear sensor closed = brake lining wear
limit exceeded) while the ignition switch is in the On
position, the brake wear indicator is illuminated. The
indicator remains illuminated until the brake wear
sense input to the cluster is an open circuit (brake
wear sensor open = brake lining wear within limits),
or until the ignition switch is turned to the Off posi-
tion, whichever occurs first.
A brake wear sensor located at each wheel provides
a hard wired ground input to the instrument cluster
circuitry through the brake wear sense circuit when-
ever the brake linings for that wheel have exceeded
their wear limits. The four normally open brake wear
sensors are connected in parallel between ground and
instrument cluster. The brake wear sensors and their
input circuit to the instrument cluster can be diag-
nosed using conventional diagnostic tools and meth-
ods. For proper diagnosis of the instrument cluster
circuitry that controls the brake wear indicator, a
DRBIIItscan tool is required. Refer to the appropri-
ate diagnostic information.
CHARGING INDICATOR
DESCRIPTION
A charging indicator is standard equipment on all
instrument clusters. The charging indicator is located
near the lower edge of the instrument cluster, to the
left of the multi-function indicator display. The
charging indicator consists of the International Con-
trol and Display Symbol icon for ªBattery Charging
Conditionº imprinted within a rectangular cutout in
the opaque layer of the instrument cluster overlay.
The dark outer layer of the overlay prevents the indi-
cator from being clearly visible when it is not illumi-
nated. A red Light Emitting Diode (LED) behind the
cutout in the opaque layer of the overlay causes the
icon to appear silhouetted against a red field through
the translucent outer layer of the overlay when the
indicator is illuminated from behind by the LED,
which is soldered onto the instrument cluster elec-
tronic circuit board. The charging indicator is ser-
viced as a unit with the instrument cluster.
OPERATION
The charging indicator gives an indication to the
vehicle operator when the electrical system voltage is
too low. This indicator is controlled by a transistor on
the instrument cluster circuit board based upon clus-
ter programming and a hard wired input from the
generator. The charging indicator Light EmittingDiode (LED) is completely controlled by the instru-
ment cluster logic circuit, and that logic will only
allow this indicator to operate when the instrument
cluster detects that the ignition switch is in the On
position. Therefore, the LED will always be off when
the ignition switch is in any position except On. The
LED only illuminates when it is provided a path to
ground by the instrument cluster transistor. The
instrument cluster will turn on the charging indica-
tor for the following reasons:
²Bulb Test- Each time the ignition switch is
turned to the On position with the engine not run-
ning the charging indicator is illuminated by the
instrument cluster as a bulb test.
²Generator Input- Each time the cluster
detects that the voltage of the generator input is 12.7
volts or lower while the engine is running, the charg-
ing indicator will be illuminated. The indicator
remains illuminated until the cluster detects that the
voltage of the generator input is above 12.7 volts, or
until the ignition switch is turned to the Off position,
whichever occurs first.
The generator provides a hard wired input to the
instrument cluster circuitry on the engine running
(D+) circuit. If the instrument cluster turns on the
indicator while the engine is running, it may indicate
that the charging system requires service. The gener-
ator input circuit to the instrument cluster can be
diagnosed using conventional diagnostic tools and
methods. For proper diagnosis of the charging sys-
tem, or the instrument cluster circuitry that controls
the charging indicator, a DRBIIItscan tool is
required. Refer to the appropriate diagnostic infor-
mation.
CLOCK
DESCRIPTION
An electronic digital clock is standard equipment
on all instrument clusters. In vehicles equipped with
the optional ambient temperature indicator, the clock
indication can be toggled with the ambient tempera-
ture indication on the right side of the multi-function
indicator Liquid Crystal Display (LCD) located near
the lower edge of the instrument cluster, directly
below the speedometer. The clock provides a 12 hour-
based, digital indication of the current hours and
minutes. The indications of the clock are not visible
when the LCD is not illuminated. When illuminated
the indications appear as dark characters silhouetted
against an amber field. When the exterior lighting is
turned Off, the display is illuminated at maximum
brightness. When the exterior lighting is turned On
the display illumination level can be adjusted in con-
cert with the cluster general illumination lighting
VAINSTRUMENT CLUSTER 8J - 13
BRAKE WEAR INDICATOR (Continued)

using the ª+º (plus) and ª2º (minus) multi-function
indicator push buttons. The clock is serviced as a
unit with the instrument cluster.
OPERATION
The clock gives an indication to the vehicle opera-
tor of the current time. The electronic digital clock is
controlled by the instrument cluster microprocessor
based upon cluster programming. The clock display is
completely controlled by the instrument cluster logic
circuit, and that logic will only allow this indication
to be viewed when the multi-function indicator Liq-
uid Crystal Display (LCD) is activated. However, the
clock remains functional regardless of the ignition
switch position.
The vehicle operator can choose to have the
optional ambient temperature indicator displayed
instead of the clock information, but the clock and
ambient temperature indicator cannot be displayed
at the same time. The clock or ambient temperature
indicator display option is selected using the multi-
function indicator clock switch on the instrument
cluster circuit board. This switch is actuated manu-
ally by depressing the clock switch push button that
extends through the lower edge of the cluster lens
below the left end of the multi-function indicator.
Actuating this switch momentarily will toggle the
display between the clock and ambient temperature
indicator modes. Actuating this switch twice within
about one second will cause the display to toggle, but
then automatically revert to the originally selected
mode after about twenty seconds.
See the owner's manual in the vehicle glove box for
more information on the features, use, operation and
setting procedures for the clock. For proper testing of
the instrument cluster circuitry that controls the
clock functions, a DRBIIItscan tool is required.
Refer to the appropriate diagnostic information.
COOLANT LOW INDICATOR
DESCRIPTION
A coolant low indicator is standard equipment on
all instrument clusters. The coolant low indicator is
located near the lower edge of the instrument cluster,
to the left of the multi-function indicator display. The
coolant low indicator consists of the International
Control and Display Symbol icon for ªLow Engine
Coolantº imprinted within a rectangular cutout in
the opaque layer of the instrument cluster overlay.
The dark outer layer of the overlay prevents the indi-
cator from being clearly visible when it is not illumi-
nated. A red Light Emitting Diode (LED) behind the
cutout in the opaque layer of the overlay causes the
icon to appear silhouetted against a red field throughthe translucent outer layer of the overlay when the
indicator is illuminated from behind by the LED,
which is soldered onto the instrument cluster elec-
tronic circuit board. The coolant low indicator is ser-
viced as a unit with the instrument cluster.
OPERATION
The coolant low indicator gives an indication to the
vehicle operator when the engine coolant level is low.
This indicator is controlled by a transistor on the
instrument cluster circuit board based upon cluster
programming and a hard wired input received by the
cluster from the engine coolant level switch. The cool-
ant low indicator Light Emitting Diode (LED) is com-
pletely controlled by the instrument cluster logic
circuit, and that logic will only allow this indicator to
operate when the instrument cluster detects that the
ignition switch is in the On position. Therefore, the
LED will always be off when the ignition switch is in
any position except On. The LED only illuminates
when it is provided a path to ground by the instru-
ment cluster transistor. The instrument cluster will
turn on the coolant low indicator for the following
reasons:
²Bulb Test- Each time the ignition switch is
turned to the On position the coolant low indicator is
illuminated for about two seconds as a bulb test.
²Engine Coolant Level Switch Input- Each
time the cluster detects an appropriate input on the
low coolant fluid level sense circuit (engine coolant
level switch resistance low = engine coolant level low)
while the ignition switch is in the On position, the
coolant low indicator will be illuminated. The indica-
tor remains illuminated until the low coolant fluid
level sense input to the cluster changes (engine cool-
ant level switch resistance high = engine coolant
level full), or until the ignition switch is turned to
the Off position, whichever occurs first. The engine
coolant level switch also features a diagnostic resis-
tor connected in parallel between the switch input
and output to provide the cluster with verification
that the low coolant fluid level sense circuit is not
open or shorted.
The engine coolant level switch integral to the cool-
ant bottle provides a hard wired input to the instru-
ment cluster circuitry through the low coolant fluid
level sense circuit. The engine coolant level switch
and the low coolant fluid level sense circuit to the
instrument cluster can be diagnosed using conven-
tional diagnostic tools and methods. For proper diag-
nosis of the instrument cluster circuitry that controls
the coolant low indicator, a DRBIIItscan tool is
required. Refer to the appropriate diagnostic infor-
mation.
8J - 14 INSTRUMENT CLUSTERVA
CLOCK (Continued)