2006 MERCEDES-BENZ SPRINTER engine

Located between the rear cover and the cluster
hood is the cluster housing. The molded plastic clus-
ter housing serves as the carrier for the cluster elec-
tronic circuit board and circuitry, the cluster
connector receptacles, the gauges, a Light Emitting
Diode (LED) for each cluster indicator and general
illumination lamp, the multi-function indicator LCD
unit, electronic tone generators, the cluster overlay,
the gauge pointers, the multi-function indicator
switches and the four switch push buttons.
The cluster overlay is a laminated plastic unit. The
dark, visible, outer surface of the overlay is marked
with all of the gauge dial faces and graduations, but
this layer is also translucent. The darkness of this
outer layer prevents the cluster from appearing clut-
tered or busy by concealing the cluster indicators
that are not illuminated, while the translucence of
this layer allows those indicators and icons that are
illuminated to be readily visible. The underlying
layer of the overlay is opaque and allows light from
the LED for each of the various indicators and illu-
mination lamps behind it to be visible through the
outer layer of the overlay only through predeter-
mined cutouts. A rectangular opening in the overlay
at the base of the speedometer provides a window
through which the illuminated multi-function indica-
tor LCD unit can be viewed.
Several versions of the EMIC module are offered
on this model. These versions accommodate all of the
variations of optional equipment and regulatory
requirements for the various markets in which the
vehicle will be offered. The microprocessor-based
EMIC utilizes integrated circuitry, Electrically Eras-
able Programmable Read Only Memory (EEPROM)
type memory storage, information carried on the
Controller Area Network (CAN) data bus, along with
several hard wired analog and multiplexed inputs to
monitor systems, sensors and switches throughout
the vehicle.
In response to those inputs, the hardware and soft-
ware of the EMIC allow it to control and integrate
many electronic functions and features of the vehicle
through both hard wired outputs and the transmis-
sion of electronic message outputs to other electronic
modules in the vehicle over the CAN data bus. (Refer
to 8 - ELECTRICAL/ELECTRONIC CONTROL
MODULES/COMMUNICATION - DESCRIPTION -
CAN BUS).
Besides typical instrument cluster gauge and indi-
cator support, the electronic functions and features
that the EMIC supports or controls include the fol-
lowing:
²Active Service System- In vehicles equipped
with the Active Service SYSTem (ASSYST) engine oil
maintenance indicator option, the EMIC electronic
circuit board includes a second dedicated micropro-
cessor. This second microprocessor evaluates various
data including time, mileage, and driving conditionsto calculate the required engine oil service intervals,
and provides both visual and audible alerts to the
vehicle operator when certain engine oil maintenance
services are required.
²Audible Warnings- The EMIC electronic cir-
cuit board is equipped with an audible tone generator
and programming that allows it to provide various
audible alerts to the vehicle operator, including buzz-
ing and chime tones. An audible contactless elec-
tronic relay is also soldered onto the circuit board to
produce audible clicks that is synchronized with turn
signal indicator flashing to emulate the sounds of a
conventional turn signal or hazard warning flasher.
These audible clicks can occur at one of two rates to
emulate both normal and bulb-out turn or hazard
flasher operation. (Refer to 8 - ELECTRICAL/
CHIME/BUZZER - DESCRIPTION).
²Panel Lamps Dimming Control- The EMIC
provides a hard wired 12-volt Pulse-Width Modulated
(PWM) output that synchronizes the dimming level
of all panel lamps dimmer controlled lamps with that
of the cluster general illumination lamps and multi-
function indicator.
The EMIC houses four analog gauges and has pro-
visions for up to nineteen indicators (Fig. 3). The
EMIC includes the following analog gauges:
²Coolant Temperature Gauge
²Fuel Gauge
²Speedometer
²Tachometer
The EMIC includes provisions for the following
indicators (Fig. 3):
²Airbag (SRS) Indicator
²Antilock Brake System (ABS) Indicator
²Brake Indicator
²Brake Wear Indicator
²Charging Indicator
²Clogged Fuel Filter Indicator
²Constant Engine Speed (ADR) Indicator
²Coolant Low Indicator
²Electronic Stability Program (ESP) Indica-
tor
²High Beam Indicator
²Low Fuel Indicator
²Malfunction Indicator Lamp (MIL)
²Multi-Function Indicator (LCD)
²Park Brake Indicator
²Seatbelt Indicator
²Traction Control (ASR) Indicator
²Traction Control (ASR) Malfunction Indica-
tor
²Turn Signal (Right and Left) Indicators
²Washer Fluid Indicator
²Wait-To-Start Indicator
²Water-In-Fuel Indicator
VAINSTRUMENT CLUSTER 8J - 3

Except for the indications provided within the
multi-function indicator LCD unit, each indicator in
the EMIC is illuminated by a dedicated LED that is
soldered onto the EMIC electronic circuit board.
Cluster illumination is accomplished by dimmable
LED back lighting, which illuminates the gauges for
visibility when the exterior lighting is turned on. The
cluster general illumination LED units are also sol-
dered onto the EMIC electronic circuit board. The
LED units are not available for service replacement
and, if damaged or faulty, the entire EMIC must be
replaced.Hard wired circuitry connects the EMIC to the
electrical system of the vehicle. These hard wired cir-
cuits are integral to the vehicle wire harnesses,
which are routed throughout the vehicle and retained
by many different methods. These circuits may be
connected to each other, to the vehicle electrical sys-
tem and to the EMIC through the use of a combina-
tion of soldered splices, splice block connectors, and
many different types of wire harness terminal con-
nectors and insulators. Refer to the appropriate wir-
ing information. The wiring information includes
wiring diagrams, proper wire and connector repair
Fig. 3 Gauges & Indicators
1 - AIRBAG INDICATOR 16 - SEATBELT INDICATOR
2 - TACHOMETER 17 - ABS INDICATOR
3 - LEFT TURN INDICATOR 18 - MULTI-FUNCTION INDICATOR PLUS/MINUS SWITCH
PUSH BUTTONS
4 - SPEEDOMETER 19 - MULTI-FUNCTION INDICATOR (INCLUDES: CLOCK, GEAR
SELECTOR INDICATOR, ODOMETER, TRIP ODOMETER, EN-
GINE OIL LEVEL DATA, AMBIENT TEMPERATURE INDICATOR
[OPTIONAL], & ACTIVE SERVICE SYSTEM [ASSYST] ENGINE
OIL MAINTENANCE INDICATOR [OPTIONAL])
5 - TRACTION CONTROL INDICATOR 20 - MULTI-FUNCTION INDICATOR MODE (MILES [KILOME-
TERS]/TIME) SWITCH PUSH BUTTONS
6 - RIGHT TURN INDICATOR 21 - COOLANT LOW INDICATOR
7 - ENGINE TEMPERATURE GAUGE 22 - BRAKE INDICATOR
8 - FUEL GAUGE 23 - OIL LEVEL INDICATOR
9 - WAIT-TO-START INDICATOR 24 - BRAKE WEAR INDICATOR
10 - WASHER FLUID INDICATOR (OPTIONAL) 25 - WATER-IN-FUEL INDICATOR
11 - CONSTANT ENGINE SPEED (ADR) INDICATOR (OPTION-
AL)26 - CHARGING INDICATOR
12 - LOW FUEL INDICATOR 27 - HIGH BEAM INDICATOR
13 - TRACTION CONTROL MALFUNCTION INDICATOR 28 - PARK BRAKE INDICATOR
14 - MALFUNCTION INDICATOR LAMP 29 - FUEL FILTER CLOGGED INDICATOR
15 - ELECTRONIC STABILITY PROGRAM (ESP) INDICATOR
(OPTIONAL)
8J - 4 INSTRUMENT CLUSTERVA

INDICATORS
Indicators are located in various positions within
the EMIC and are all connected to the EMIC elec-
tronic circuit board. The ambient temperature indica-
tor (optional), brake indicator, brake wear indicator,
charging indicator, coolant low indicator, high beam
indicator, low fuel indicator, park brake indicator,
seatbelt indicator, turn signal indicators, and washer
fluid indicator operate based upon hard wired inputs
to the EMIC. The airbag (SRS) indicator is normally
controlled by a hard wired input from the Airbag
Control Module (ACM); however, if the EMIC sees an
abnormal or no input from the ACM, it will automat-
ically turn the airbag indicator On until the hard
wired input from the ACM has been restored. The
Malfunction Indicator Lamp (MIL) is normally con-
trolled by CAN data bus messages from the Engine
Control Module (ECM); however, if the EMIC loses
CAN data bus communication, the EMIC circuitry
will automatically turn the MIL on until CAN data
bus communication is restored. The EMIC uses CAN
data bus messages from the ECM, the ACM, and the
Controller Antilock Brake to control all of the
remaining indicators.
The various EMIC indicators are controlled by dif-
ferent strategies; some receive battery feed from the
EMIC circuitry and have a switched ground, while
others are grounded through the EMIC circuitry and
have a switched battery feed. However, all indicators
are completely controlled by the EMIC microproces-
sor based upon various hard wired and electronic
message inputs. Except for the indications provided
by the multi-function indicator Liquid Crystal Dis-
play (LCD) unit, all indicators are illuminated at a
fixed intensity, which is not affected by the selected
illumination intensity of the EMIC general illumina-
tion lamps.
The hard wired indicator inputs may be diagnosed
using conventional diagnostic methods. However,
proper testing of the EMIC circuitry and the CAN
bus message controlled indicators requires the use of
a diagnostic scan tool. Refer to the appropriate diag-
nostic information. Specific details of the operation
for each indicator may be found elsewhere in this
service information.
CLUSTER ILLUMINATION
The EMIC has several general illumination lamps
that are illuminated when the exterior lighting is
turned on with the multi-function switch. The illumi-
nation intensity of these lamps is adjusted by a dim-
ming level input received from the multi-function
indicator ª+º (plus) and ª±º (minus) switch push but-
tons that extend through the lower edge of the clus-
ter lens below the right end of the multi-function
indicator. When the exterior lighting is turned Off,
the display is illuminated at maximum brightness.
When the exterior lighting is turned On and thetransmission gear selector is in the Park position,
depressing the plus switch push button brightens the
display lighting, and depressing the minus switch
push button dims the display lighting. The EMIC
also provides a Pulse-Width Modulated (PWM) panel
lamps dimmer output that can be used to synchro-
nize the illumination lighting levels of external illu-
mination lamps (up to about 23 to 30 watts) with
that of the EMIC.
The hard wired multi-function switch input and
the EMIC panel lamps dimmer output may be diag-
nosed using conventional diagnostic methods. How-
ever, proper testing of the PWM control of the EMIC
and the electronic dimming level inputs from the
multi-function indicator push buttons requires the
use of a diagnostic scan tool. Refer to the appropriate
diagnostic information.
INPUT AND OUTPUT CIRCUITS
HARD WIRED INPUTS
The hard wired inputs to the EMIC include the fol-
lowing:
NOTE: Final approved circuit names were not yet
available at the time this information was compiled.
²Airbag Indicator Driver
²Ambient Temperature Sensor Signal
(Optional)
²Brake Wear Indicator Sense
²Charging Indicator Driver
²Coolant Level Switch Sense
²Front Door Jamb Switch Sense
²Fuel Level Sensor Signal
²Fused B(+)
²Fused Ignition Switch Output
²High Beam Indicator Driver
²Key-In Ignition Switch Sense
²Left Turn Signal
²Park Brake Switch Sense
²Right Turn Signal
²Seat Belt Switch Sense
²Washer Fluid Switch Sense (Optional)
Refer to the appropriate wiring information for
additional details.
HARD WIRED OUTPUTS
The hard wired outputs of the EMIC include the
following:
²Engine Running Relay Control
²Panel Lamps Driver
Refer to the appropriate wiring information for
additional details.
8J - 6 INSTRUMENT CLUSTERVA

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.
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 diagnostic scan tool is
required. Refer to the appropriate diagnostic infor-
mation.
ADR INDICATOR
DESCRIPTION
A constant engine speed (ADR) indicator is stan-
dard equipment on all instrument clusters, but is
only functional on vehicles equipped with the
optional ADR switch. The ADR indicator is located
near the lower edge of the instrument cluster, to the
right of the multi-function indicator display. The
ADR indicator consists of the text ªADRº 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 text 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 ADR indicator is serviced as a unit with
the instrument cluster.
OPERATION
The constant engine speed (ADR) indicator gives
an indication to the vehicle operator concerning the
operating status of the constant engine speed (ADR)
feature. The ADR indicator is controlled by a transis-
tor on the instrument cluster circuit board based
upon cluster programming and electronic messages
received by the cluster from the Engine Control Mod-
ule (ECM) over the Controller Area Network (CAN)
data bus. The ADR 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 traction control indicator for
the following reasons:
²Constant Engine Speed (ADR) Indicator
Lamp-On Message- Each time the cluster receives
an ADR indicator lamp-on message from the ECM,
the indicator will be illuminated. The indicator is
illuminated when the ADR feature has been acti-
vated with the ADR switch, and is turned off when
the ADR feature is deactivated with the ADR switch.
The ADR indicator will be extinguished if the ADR
feature is turned off because the park brake has been
released or the vehicle is in motion. The ADR indica-
tor will also be extinguished if the service brake
pedal is depressed, but the ADR feature will auto-
matically be restored and the indicator illuminated
when the brake pedal is released. The indicator
8J - 10 INSTRUMENT CLUSTERVA

remains illuminated until the cluster receives a
lamp-off message from the ECM, or until the ignition
switch is turned to the Off position, whichever occurs
first.
The ECM continually monitors the constant engine
speed (ADR) switch and electronic messages from the
Controller Antilock Brake (CAB) concerning the sta-
tus of the four wheel speed sensors, the park brake
switch and the brake lamp switch to determine the
correct operating mode for the ADR feature. The
ECM then sends the proper lamp-on or lamp-off mes-
sages to the instrument cluster. See the owner's man-
ual in the vehicle glove box for more information on
the features, use, activation and deactivation of the
constant engine speed (ADR) feature. For proper
diagnosis of the ADR feature, the ECM, the CAB, the
CAN data bus, or the electronic message inputs to
the instrument cluster that control the ADR indica-
tor, a diagnostic scan tool is required. Refer to the
appropriate diagnostic information.
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 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 instru-
ment cluster detects that the ignition switch is in the
On position. Therefore, the LED will always be offwhen 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 diagnostic scan tool is required. Refer
to the appropriate diagnostic information.
AMBIENT TEMPERATURE
INDICATOR
DESCRIPTION
An ambient temperature indicator is optional
equipment on all instrument clusters. In vehicles so
VAINSTRUMENT CLUSTER 8J - 11

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
diagnostic scan tool is required. Refer to the appro-
priate 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 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 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 diagnostic scan 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
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
8J - 14 INSTRUMENT CLUSTERVA

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 diagnostic scan 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 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 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 logiccircuit, 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 diagnostic scan tool is
required. Refer to the appropriate diagnostic infor-
mation.
ENGINE TEMPERATURE
GAUGE
DESCRIPTION
An engine coolant temperature gauge is standard
equipment on all instrument clusters. The engine
coolant temperature gauge is located in the upper
right corner of the instrument cluster, to the right of
the speedometer. The engine coolant temperature
gauge consists of a movable gauge needle or pointer
controlled by the instrument cluster circuitry and a
fixed 45 degree scale on the cluster overlay that
reads left-to-right from 120É C to 40É C for Canadian
vehicles, or from 250É F to 110É F for United States
vehicles. An International Control and Display Sym-
bol icon for ªEngine Coolant Temperatureº is located
VAINSTRUMENT CLUSTER 8J - 15

on the cluster overlay, directly below the high end of
the scale. Just to the right of the icon, the nomencla-
ture ªÉCº or ªÉFº confirms the unit of measure for the
gauge readings.
The engine coolant temperature gauge graphics are
white against a black field, except for a single red
graduation at the far left (high) end of the gauge
scale, making them clearly visible within the instru-
ment cluster in daylight. When illuminated from
behind by the panel lamps dimmer controlled cluster
illumination lighting with the exterior lamps turned
On, the white graphics appear amber and the red
graphics appear red. The orange gauge needle is
internally illuminated. Gauge illumination is pro-
vided by Light Emitting Diode (LED) units soldered
onto the instrument cluster electronic circuit board.
The engine coolant temperature gauge is serviced as
a unit with the instrument cluster.
OPERATION
The engine coolant temperature gauge gives an
indication to the vehicle operator of the engine cool-
ant temperature. This gauge is controlled by the
instrument cluster circuit board based upon cluster
programming and electronic messages received by
the cluster from the Engine Control Module (ECM)
over the Controller Area Network (CAN) data bus.
The engine coolant temperature gauge is an air core
magnetic unit that receives battery current on the
instrument cluster electronic circuit board when the
instrument cluster detects that the ignition switch is
in the On position. The cluster is programmed to
move the gauge needle back to the low end of the
scale after the ignition switch is turned to the Off
position. The instrument cluster circuitry controls
the gauge needle position and provides the following
features:
²Engine Temperature Normal Message- Each
time the cluster receives a message from the ECM
indicating the engine coolant temperature is within
the normal operating range [up to about 120É C (250É
F), the gauge needle is moved to the actual relative
temperature position on the gauge scale.
²Engine Temperature High Message- Each
time the cluster receives a message from the ECM
indicating the engine coolant temperature is high
[above about 120É C (250É F) the gauge needle is
moved into the red warning zone on the gauge scale.
The ECM continually monitors the engine coolant
temperature sensor to determine the engine operat-
ing temperature. The ECM then sends the proper
engine coolant temperature messages to the instru-
ment cluster. If the instrument cluster moves the
engine coolant temperature gauge needle to red area
of the gauge scale, it may indicate that the engine or
the engine cooling system require service. For proper
diagnosis of the engine coolant temperature sensor,
the ECM, the CAN data bus, the electronic messageinputs to the instrument cluster, or the instrument
cluster circuitry that controls the engine coolant tem-
perature gauge, a diagnostic scan tool is required.
Refer to the appropriate diagnostic information.
ESP INDICATOR
DESCRIPTION
An Electronic Stability Program (ESP) indicator is
standard equipment on all instrument clusters, but is
only functional on vehicles equipped with the
optional ESP system. The ESP indicator is located
near the lower edge of the instrument cluster, to the
right of the multi-function indicator display. The ESP
indicator consists of a stencil-like cutout of the text
ªESPº 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 text to appear in amber through the
translucent outer layer of the overlay when the indi-
cator is illuminated from behind by the LED, which
is soldered onto the instrument cluster electronic cir-
cuit board. The ESP indicator is serviced as a unit
with the instrument cluster.
OPERATION
The ESP indicator gives an indication to the vehi-
cle operator when the ESP system is faulty or inop-
erative. 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 ESP 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 ESP indicator for the following reasons:
²Bulb Test- Each time the ignition switch is
turned to the On position the ESP indicator is illu-
minated by the cluster for about two seconds as a
bulb test.
²ESP Lamp-On Message- Each time the clus-
ter receives a lamp-on message from the CAB, the
ESP 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.
8J - 16 INSTRUMENT CLUSTERVA