2005 MERCEDES-BENZ SPRINTER display

INTERNATIONAL SYMBOLS
DESCRIPTION
The graphic symbols illustrated in the following
International Control and Display Symbols Chart
(Fig. 1) are used to identify various instrument con-
trols. The symbols correspond to the controls and dis-
plays that are located on the instrument panel.
FASTENER IDENTIFICATION
DESCRIPTION
The SAE bolt strength grades range from grade 2
to grade 8. The higher the grade number, the greaterthe bolt strength. Identification is determined by the
line marks on the top of each bolt head. The actual
bolt strength grade corresponds to the number of line
marks plus 2. The most commonly used metric bolt
strength classes are 9.8 and 10.9. The metric
strength class identification number is imprinted on
the head of the bolt. The higher the class number,
the greater the bolt strength. Some metric nuts are
imprinted with a single-digit strength class on the
nut face. Refer to the Fastener Identification and
Fastener Strength Charts (Fig. 2) and (Fig. 3).
Fig. 1 INTERNATIONAL CONTROL AND DISPLAY SYMBOLS
1 High Beam 13 Rear Window Washer
2 Fog Lamps 14 Fuel
3 Headlamp, Parking Lamps, Panel Lamps 15 Engine Coolant Temperature
4 Turn Warning 16 Battery Charging Condition
5 Hazard Warning 17 Engine Oil
6 Windshield Washer 18 Seat Belt
7 Windshield Wiper 19 Brake Failure
8 Windshield Wiper and Washer 20 Parking Brake
9 Windscreen Demisting and Defrosting 21 Front Hood
10 Ventilating Fan 22 Rear hood (Decklid)
11 Rear Window Defogger 23 Horn
12 Rear Window Wiper 24 Lighter
2 INTRODUCTIONVA

MAINTENANCE - WITH ASSYST MAINTENANCE
COMPUTER
ASSYST provides information on the best possible
timing for maintenance work.
NOTE: The engine manufacturer strongly recom-
mends the use of synthetic engine oils, such as
TMobil 1 SAE 0W-40.
When the next maintenance service is due, this
will be indicated in the multi-function display with
the wrench icon symbol displayed in km/miles or
days.
²One wrench icon showing indicates Oil Service
is necessary.
²Two wrench icons showing indicates Mainte-
nance Service is necessary ± displayed in km/miles or
days.
If the display shows the number of days, a clock
symbol will also appear in the multi-function display.
You should have the maintenance performed
within the stated period/distance.
The service indicator should be reset after an oil
service and/or maintenance service has been per-
formed.
REGULAR CHECK-UPS
To maintain the safe operation of the vehicle, it is
recommended that the following tasks be performed
on a regular basis (i.e. weekly or whenever the vehi-
cle is refueled). Check:
²Engine oil level
²Brake system, clutch mechanism ± fluid level
²Battery ± acid level
²Windshield washer system and headlamp clean-
ing system ± fluid level
²Mechanical assemblies (e. g. engine, transmis-
sion, etc.) ± check for leaks
²Condition of tires and tires pressures
²All exterior lights
SPECIAL MAINTENANCE REQUIREMENTS
If bodies built by manufacturers other than
DaimlerChrysler Corporation are fitted to the vehi-
cle, the maintenance requirements and lubrication
intervals specified by the body manufacturer must be
adhered to, in addition to all standard maintenance
requirements.
Brake Fluid
Only use brake fluids approved by the manufac-
turer (DOT 4 plus).
Coolant
Corrosion inhibitor/antifreeze concentration in the
coolant should be checked before the onset of winter
(once year in countries with high prevailing temper-
atures).Replace the coolant every five years or 100,000
miles.
Dust Filter for Heating/Ventilation Replace-
ment
The dust filter and the tailgate interior filter are to
be renewed during routine maintenance service. If
operating conditions are dusty, these filters should be
renewed more frequently.
ENGINE OIL CHANGE AND FILTER REPLACEMENT
At the minimum, change the engine oil and oil fil-
ter once a year ± even if the vehicle mileage per year
is extremely low. For standard oil service schedules
refer to the chapter oil service and maintenance ser-
vice.
Once a Year
Select the viscosity of the engine oil (SAE classes)
according to the outside air temperature.
Only use engine oil approved by DaimlerChrysler
Corporation if following the ASSYST system guide-
lines.
If the fuel used has a sulphur content exceeding
0.05% by weight, the service intervals should be split
in half.
SCOPE OF WORK FOR MAINTENANCE SERVICE
Oil Service
²Engine:
Oil change and filter replacement
Check fluid levels of the following system,
refill as necessary.
²If fluid is lost, trace and eliminate cause ± as a
separate order.
²Power-assisted steering
Lubrication work:
²Trailer tow hitch (original equipment)
Maintenance
²ASSYST maintenance computer reset
Function check
²Signalling system, warning and indicator lamps
²Headlamps, exterior lighting
²Windshield wipers, windshield washer system
Check for leaks and damage.
²Check for abrasion points and ensure that lines
are correctly routed!
²All lines and hoses, sensor cables
²Rubber boots on front axle drive shafts, rubber
boots on front axle suspension ball joints, shock
absorbers
Check fluid levels for the following systems,
correct as necessary.
NOTE: Should there be a loss of fluid which cannot
be explained by regular use, trace and eliminate the
cause.
0 - 8 LUBRICATION & MAINTENANCEVA
MAINTENANCE SCHEDULES (Continued)

battery negative terminal post and the negative cable
terminal clamp is lost during any part of the IOD
test, the electronic timer function will be activated
and all of the tests will have to be repeated.
(5) After about three minutes, the high-amperage
IOD reading on the multi-meter should become very
low or nonexistent, depending upon the electrical
equipment in the vehicle. If the amperage reading
remains high, remove and replace each fuse or circuit
breaker in the Fuse Blocks, one at a time until the
amperage reading becomes very low, or nonexistent.
Refer to the appropriate wiring information in this
service manual for complete fuseblock fuse, circuit
breaker, and circuit identification. This will isolate
each circuit and identify the circuit that is the source
of the high-amperage IOD. If the amperage reading
remains high after removing and replacing each fuse
and circuit breaker, disconnect the wire harness from
the generator. If the amperage reading now becomes
very low or nonexistent, refer to Charging System for
the proper charging system diagnosis and testing
procedures. After the high-amperage IOD has been
corrected, switch the multi-meter to progressively
lower amperage scales and, if necessary, repeat the
fuse and circuit breaker remove-and-replace process
to identify and correct all sources of excessive IOD. It
is now safe to select the lowest milliampere scale of
the multi-meter to check the low-amperage IOD.
CAUTION: Do not open any doors, or turn on any
electrical accessories with the lowest milliampere
scale selected, or the multi-meter may be damaged.
(6) Observe the multi-meter reading. The low-am-
perage IOD should not exceed thirty-five milliam-
peres (0.035 ampere). If the current draw exceeds
thirty-five milliamperes, isolate each circuit using the
fuse and circuit breaker remove-and-replace process
in Step 5. The multi-meter reading will drop to
within the acceptable limit when the source of the
excessive current draw is disconnected. Repair this
circuit as required; whether a wiring short, incorrect
switch adjustment, or a component failure is at fault.
STANDARD PROCEDURE - USING MICRO 420
BATTERY TESTER
Always use the Micro 420 Instruction Manual that
was supplied with the tester as a reference. If the
Instruction Manual is not available the following pro-
cedure can be used:
WARNING: ALWAYS WEAR APPROPRIATE EYE
PROTECTION AND USE EXTREME CAUTION WHEN
WORKING WITH BATTERIES.
BATTERY TESTING
(1) If testing the battery OUT-OF-VEHICLE, clean
the battery terminals with a wire brush before test-
ing. If the battery is equipped with side post termi-
nals, install and tighten the supplied lead terminal
stud adapters. Do not use steel bolts. Failure to prop-
erly install the stud adapters, or using stud adapters
that are dirty or worn-out may result in false test
readings.
(2) If testing the battery IN-THE-VEHICLE, make
certain all of the vehicle accessory loads are OFF,
including the ignition.The preferred test position
is at the battery terminal. If the battery is not
accessible, you may test using both the positive and
negative jumper posts. Select TESTING AT JUMPER
POST when connecting to that location.
(3) Connect the tester (Fig. 6) to the battery or
jumper posts, the red clamp to positive (+) and the
black clamp to negative (±).
NOTE: Multiple batteries connected in parallel must
have the ground cable disconnected to perform a
battery test. Failure to disconnect may result in
false battery test readings.
(4) Using the ARROW key selectinoroutof vehi-
cle testing and press ENTER to make a selection.
(5) If not selected, choose the Cold Cranking Amp
(CCA) battery rating. Or select the appropriate bat-
tery rating for your area (see menu). The tester will
then run its self programmed test of the battery and
display the results. Refer to the test result table
noted below.
Fig. 6 Micro 420 Battery Tester
VABATTERY SYSTEM 8F - 11
BATTERY (Continued)

INSTRUMENT CLUSTER
DESCRIPTION
The instrument cluster for this model is an Elec-
troMechanical Instrument Cluster (EMIC) that is
located above the steering column opening in the
instrument panel, directly in front of the driver (Fig.
1). The remainder of the EMIC, including the mounts
and the electrical connections, are concealed within
the instrument panel behind the cluster bezel and
beneath the instrument panel top cover for the clus-
ter. The instrument cluster includes analog gauges,
meters, indicators, and acoustic signal transmitters.
The EMIC module also incorporates a multi-func-
tion indicator that consists of a digital Liquid Crystal
Display (LCD) unit for displaying odometer/trip
odometer information, an electronic digital clock,
engine oil level information, automatic transmission
gear selector position (PRNDL), and certain diagnos-
tic information. The multi-function indicator also has
four push button switches, which provide the vehicle
operator with an interface to adjust certain inputs to
the instrument cluster and to select from multiple
display options. If the vehicle is equipped with the
appropriate options, the multi-function indicator also
provides an outside ambient temperature indicator
display and an Active Service SYStem (ASSYST)
engine oil maintenance indicator to display engine oil
level and maintenance reminders.
The EMIC gauges and indicators are visible
through a dedicated opening in the cluster bezel on
the instrument panel and are protected by a clear
plastic cluster lens (Fig. 2) that is secured by eightintegral latches to the molded black plastic cluster
hood. Four, black plastic multi-function indicator
switch push buttons protrude through dedicated
holes in a rectangular black plastic switch bezel that
is integral to the cluster lens and located near the
lower edge of the cluster directly below the multi-
function indicator LCD unit. The cluster hood serves
as a visor and shields the face of the cluster from
ambient light and reflections to reduce glare. The
cluster hood has eight integral latches that engage
eight integral latch tabs on the cluster rear cover,
sandwiching the cluster housing unit between the
hood and the rear cover. The cluster hood also has
two integral pivot loops molded into its underside
that engage two pairs of molded pivot hooks that are
integral to the top of the instrument panel base
structure. These pivots allow the cluster to be rolled
rearward to ease service access to the wire harness
connectors at the back of the cluster.
The rear of the cluster housing and the EMIC elec-
tronic circuitry are protected by the molded plastic
rear cover. A mounting ear at each upper corner of
the rear cover are used to secure the EMIC to the
molded plastic instrument panel base unit with two
screws. The rear cover includes clearance holes for
the two cluster connector receptacles on the cluster
electronic circuit board. The connector receptacles on
the back of the cluster electronic circuit board con-
nect the EMIC to the vehicle electrical system
through two take outs with connectors from the vehi-
cle wire harness. The EMIC rear cover includes a
molded mounting tab and a latch feature that
secures the RKE/immobilizer module to the back of
the cluster. The RKE/immobilizer module is con-
nected to the vehicle electrical system through a sep-
Fig. 1 Instrument Cluster
1 - COVER
2 - BEZEL
3 - INSTRUMENT CLUSTER
4 - STEERING WHEEL
5 - MULTI-FUNCTION SWITCH
6 - SPEED CONTROL SWITCH
Fig. 2 Instrument Cluster Components
1 - LENS
2 - HOOD
3 - CLUSTER HOUSING
4 - REAR COVER
8J - 2 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, seatbelt indicator, turn
signal indicators, and washer fluid indicator operate
based upon hard wired inputs to the EMIC. The air-
bag (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 automatically turn the airbag
indicator On until the hard wired input from the
ACM has been restored. The Malfunction Indicator
Lamp (MIL) is normally controlled by CAN data bus
messages from the Engine Control Module (ECM);
however, if the EMIC loses CAN data bus communi-
cation, 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 DRBIIItscan 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 the
transmission 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 DRBIIItscan 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:
NOTE: Final approved circuit names were not yet
available at the time this information was compiled.
²Engine Running Relay Control
²Panel Lamps Driver
8J - 6 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)

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)