2006 MERCEDES-BENZ SPRINTER Dash

TABLE OF CONTENTS - Continued
8.9VEHICLE THEFT SECURITY SYSTEM................................254
8.9.1SECURITY SYSTEM MODULE..............................254
8.9.2INTRUSION SENSORS....................................254
8.9.3SWITCHES..............................................255
8.9.4SIREN..................................................255
9.0 CONNECTOR PINOUTS................................................257
A/C AUXILIARY FAN....................................................257
AIR OUTLET TEMPERATURE SENSOR...................................257
AIRBAG CONTROL MODULE - YELLOW...................................257
AIRBAG SQUIB-DRIVER - YELLOW.......................................258
AIRBAG SQUIB-PASSENGER - YELLOW..................................258
AMBIENT TEMPERATURE SENSOR......................................258
AUTOMATIC TEMPERATURE CONTROL MODULE C1 - BROWN..............259
AUTOMATIC TEMPERATURE CONTROL MODULE C2.......................259
AUXILIARY HEATER CONTROL..........................................259
BLOWER MOTOR RESISTOR BLOCK.....................................259
BLOWER MOTOR-FRONT - BLACK.......................................260
C205 - YELLOW (DASH SIDE)...........................................260
C205 - YELLOW (MAIN BODY SIDE)......................................260
CENTRAL TIMER MODULE C1 - PINK.....................................260
CENTRAL TIMER MODULE C2 - LT. GREEN...............................261
CIRCULATION PUMP (CABIN HEATER MODULE)...........................261
CIRCULATION PUMP (REST SYSTEM)....................................261
CIRCULATION PUMP DIODE............................................261
CLOCKSPRING C2 - YELLOW...........................................262
CONTROLLER ANTILOCK BRAKE........................................262
CYLINDER LOCK SWITCH-DRIVER.......................................263
DATA LINK CONNECTOR - BLACK........................................263
DOOR LOCK MOTOR/AJAR SWITCH ASSEMBLY-DRIVER C1.................263
DOOR LOCK MOTOR/AJAR SWITCH ASSEMBLY-DRIVER C2.................263
DOOR LOCK MOTOR/AJAR SWITCH ASSEMBLY-LEFT SLIDING C1...........263
DOOR LOCK MOTOR/AJAR SWITCH ASSEMBLY-LEFT SLIDING C2...........264
DOOR LOCK MOTOR/AJAR SWITCH ASSEMBLY-PASSENGER C1............264
DOOR LOCK MOTOR/AJAR SWITCH ASSEMBLY-PASSENGER C2............264
DOOR LOCK MOTOR/AJAR SWITCH ASSEMBLY-REAR C1...................264
DOOR LOCK MOTOR/AJAR SWITCH ASSEMBLY-REAR C2...................264
DOOR LOCK MOTOR/AJAR SWITCH ASSEMBLY-RIGHT SLIDING C1..........265
DOOR LOCK MOTOR/AJAR SWITCH ASSEMBLY-RIGHT SLIDING C2..........265
DOSING PUMP........................................................265
ENGINE CONTROL MODULE C1 (EXCEPT OBD) - BLACK...................265
ENGINE CONTROL MODULE C2 (EXCEPT OBD) - BLACK...................266
ENGINE CONTROL MODULE C2 (OBD)...................................267
ENGINE CONTROL MODULE C3 (EXCEPT OBD) - BLACK...................268
EVAPORATOR TEMPERATURE SENSOR..................................269
FUEL LEVEL SENSOR..................................................269
FUSES (FUSE BLOCK NO. 1)............................................271
FUSE BLOCK NO. 1 C1.................................................271
FUSE BLOCK NO. 1 C2.................................................271
FUSE BLOCK NO. 1 C3 - BLACK.........................................272
FUSE BLOCK NO. 1 C4 - BLACK.........................................272
FUSE BLOCK NO. 1 C5 - BLACK.........................................272
vi

Static Heater Signal
A status of9ON9indicates that the heater module
sees the9Stationary Heating Mode ON9signal after
switching on the heater with the heater timer or the
auxiliary heater switch. A status of9OFF9indicates
that the9Stationary Heating Mode ON9signal is
not present at the heater module.
Heater Booster Mode Signal
A status of9ON9indicates that the heater module
sees the9Heater Booster Mode ON9signal after
switching on the heater with the auxiliary heater
switch. A status of9OFF9indicates that the9Heater
Booster Mode ON9signal is not present at the
heater module.
3.4 INSTRUMENT CLUSTER
The Instrument Cluster has easy-to-read instru-
ments, is capable of CAN bus communication and
provides a diagnostic function. The Instrument
Cluster with analog speedometer, tachometer, fuel
and coolant temperature gauges comes in two ver-
sions.
²Speedometer with outer miles-per-hour (mph)
scale and inner kilometers-per-hour (km/h) scale.
Coolant temperature is indicated in Fahrenheit
(for US).
²Speedometer with outer kilometers-per-hour
(km/h) scale and inner miles-per-hours (mph)
scale. Coolant temperature is indicated in de-
grees Celsius (for Canada).
Below the speedometer, there is a LCD multi-
function indicator in clear view of the driver. Warn-
ing and indicator lights (based on colored light
emitting diodes) are located in the bottom of the
instrument cluster with the exception of the turn
signal indicator lights, ASR warning light and re-
serve fuel warning light. The warning lights for the
seat belt usage and parking brake/brake fluid level
are located in the line above the bottom line. The
indicator that illuminates up when the parking
brake is applied or the brake fluid level is low is
different for U.S. and Canada.
When the key is turned to the 2nd position in the
ignition, the function of the following indicator
lights is checked automatically: High Beam ON,
Preheating, airbag malfunction. In case of a broken
LED of the airbag malfunction light, the seat belt
usage warning light will flash for 6 seconds after
the function check is finished. The Instrument
Cluster is operated with the help of 4 buttons
located below the multifunction indicator. The back-
lighting for the instrument cluster uses yellow
LED's and can be adjusted electronically to daylight
and darkness.The instrument cluster includes a warning
buzzer, which sounds (in addition to a warning light
in some cases) when:
²The headlights are on with the ignition off and
the door opened.
²The driver 's seat belt is not fastened with the
ignition on.
²The key is in the ignition and the door is open.
²Critical ASSYST information is displayed in the
multifunction indicator.
3.5 POWER DOOR LOCKS/RKE
3.5.1 CENTRAL LOCKING
The Central Locking System locks all vehicle
doors if any door is locked from the inside or
mechanically locked with the key from the outside.
However, unlocking any door, in that manner, will
only unlock that particular door. The Master Door
Lock Switch on the dash enables the operator to
lock/unlock all doors. By pressing the top of the
rocker type switch once, all doors will lock. Pressing
the switch again will unlock all doors. Pressing the
lower part of the switch once will lock all doors
except the driver door. Pressing the lower part
again will unlock all doors except the driver door. If
the Central Locking System automatically unlocks
after the vehicle was attempted to be locked, at
least one door is not properly closed.
There are two LED indicators in the Master Door
Lock Switch. The left indicator is for the driver door
and the right indicator is for all passenger/cargo
doors. These will indicate if a door is ajar or if the
doors are locked. The door ajar switches are part of
the door lock motor and are mounted in the door
latch assembly.
Inside each door lock motor there is a command
switch. The command switch is operated by the
plunger and signals any change in the lock status,
locked or unlocked. Each command switch is wired
to the Central Timer Module (CTM) sometimes
referred to as the Central Locking Module. If all
doors are closed and are unlocked, and any door is
locked by the key or the interior handle, thereby
changing the command switch, all doors will be
locked. If one of the door lock motors does not reach
the end position after a locking command, it will be
detected by the CTM (command switch not in
9Locked9position) and the vehicle will be unlocked.
3.5.2 REMOTE KEYLESS ENTRY (RKE)
The SKREEM is a combination of the Remote
Keyless Entry Module and the SKIM (Sentry Key
Immobilizer Module). It is located behind the In-
strument Cluster and has an antenna that goes up
9
GENERAL INFORMATION

BLOWER MOTOR-FRONT - BLACKCAV CIRCUIT FUNCTION
1 12RD/BL BLOWER MOTOR (+)
2 12BK GROUND
C205 - YELLOW (DASH SIDE)CAV CIRCUIT
1 20BL/DG
2 20BR/DG
C205 - YELLOW (MAIN BODY SIDE)CAV CIRCUIT
1 20BL/DG
2 20BR/DG
CENTRAL TIMER MODULE C1 - PINKCAV CIRCUIT FUNCTION
1 16DG/BK DRIVER DOOR UNLOCK SENSE
2 16BL/RD DRIVER DOOR LOCK DRIVER
3 16BK/RD DRIVER DOOR UNLOCK DRIVER
4 16YL/BK DRIVER DOOR LOCK SENSE
5 16DG/BL/WT PASSENGER FRONT DOOR UNLOCK SENSE
6 16YL/BL PASSENGER FRONT DOOR LOCK SENSE
7 16WT/YL MASTER DOOR LOCK SWITCH SENSE-ALL DOORS
8 16RD/BK FUSED D(+) RELAY NO. 1 OUTPUT
9 16WT/BL (EXCEPT VTSS) RKE INTERFACE
9 16WT/BL/RD (VTSS) RKE INTERFACE
10 16BK/RD FUSED IGNITION SWITCH OUTPUT (ACC-RUN-START)
11 16DG ENHANCED ACCIDENT REPORT DRIVER
12 20DG/WT/BL K-CTM/SSM
13 14RD/WT FUSED B(+)
14 14BR GROUND
15 16WT/BK DRIVER DOOR AJAR INDICATOR DRIVER
C
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S
260
CONNECTOR PINOUTS

enable the HCU to perform the brake fluid manage-
ment control as the combination/proportioning
valves.
The Bosch 5.7 system uses the CAB/HCU/Pump
Motor to make an integral electronic/hydraulic unit
which shares data with other electronic modules on
the vehicle via the CAN C Bus network. To access
DTCs from the CAB, the DRBIIItuses the K-ABS
line located in the Data Link Connector (DLC).
3.3 BRAKE ASSIST SYSTEM (HBA)
The Brake Assist System (HBA) analyzes how
hard and fast the driver wants to brake. It monitors
the brake pressure via a pressure sensor. The
passenger car brake assist system uses a vacuum
booster solenoid. The Sprinter uses the hydraulic
control unit to develop the brake pressure.
3.4 TCS (ASR)
The primary function of the Traction Control System
is to reduce wheel slip and maintain traction at the
driven wheels when the road surfaces are slippery. The
Traction Control System reduces wheel slip by applying
the brake that has lost traction. The system is designed
to operate at speeds below 50 km/h (30 mph). The
engine's torque can be reduced by the ECM via the CAN
C Bus, if necessary. The TCS can be deactivated with
switch on the dash. The Traction Control System uses
the ABS to indicate spinning tires to enable the traction
control function. The TCS software is in the CAB.
The TCS (ASR) performs the following functions:
1. Engine power derate
2. Engine deceleration regulation. If the vehicle is
on a patch of ice, the simple action of releasing
the throttle is enough to cause the rear wheels to
slip. To avoid this, the throttle input is regulated
so power drops slowly instead of abruptly. The
engine power is reduced (decelerated) as neces-
sary.
3.5 ELECTRONIC BRAKE DISTRIBUTION
(EBD)
The system was enhanced and eliminates the
need for the ALB system (load sensing valve). All
ESP equipped models will not have ALB. The EBV
system self-adapts to operating conditions. It de-
tects the vehicle's payload when the vehicle starts
and pulls away. Based on the acceleration rate
when the vehicle first pulls away from a standstill,
the system is able to calculate the actual payload.
This is a rough estimate which is used initially.
Later on, the system gathers more precise informa-
tion by monitoring the brake pressure and wheel
speed and negative slip when the driver applies thebrakes. The system will then produce a more accu-
rate calculation of payload depending on brake
retardation. The adaptation is erased when the
ignition is switched off. A new adaptation will occur
on the next driving cycle. By default, the system
acts upon the vehicle as if in an unloaded condition
(safe mode).
Once a new driving cycle begins with the vehicle
in a fully loaded condition (without having gathered
more precise information) the system will detect
ABS actuation in the front wheels and will allow
enough pressure to be applied to the rear axle, to an
extent where the wheels are just about to lock up
(maximum braking possible).
The system calculates the braking force at the
front and rear axles. If the driver applies the brakes
gently and then realizes he needs to apply the
brakes further, the EBV allows the proper pressure
to be applied to the front and rear brakes.
The EBV also contains a feature called ªcorner
brake systemº (CBS) which operates when the ve-
hicle is braked while cornering to avoid a possible
oversteering condition. The EBV monitors the
wheel speed of both rear wheels to detect when the
vehicle is cornering and allows precise brake pres-
sure application to the front and rear brakes. Also
when the brakes are applied during cornering, the
outer wheels get more of the vehicle's weight while
the inner wheels get less weight and could lose
traction (wheel lock up). The EBV system splits the
pressure between left and right sides in addition to
front and rear brakes.
3.6 VEHICLE CONTROLLING (FZR)
Vehicle controlling (FZR)requires additional
sensors to operate. The term ESP refers to the
software of the system. The term FZR refers to the
system controller. The TCS (ASR) system requires
wheel speed sensors to monitor wheel slip and CAN
bus communications to regulate engine power. In
addition to these inputs, the vehicle controlling
(FZR) requires a steering angle sensor, and a lateral
acceleration/yaw rate sensor.
The ESP system does not take the vehicle load
into account. Instead, the coefficient of friction is
calculated in a 20 millisecond period, where the
controller measures the rate at which the wheel
speed is decelerated, as brake pressure is applied to
the wheel.
3.7 SYSTEM COMPONENTS
²Controller Antilock Brake (CAB)
²Hydraulic Control Unit (HCU)
²Pump Motor
2
GENERAL INFORMATION

4.2.4 DRBIIITSAFETY INFORMATION
WARNING: EXCEEDING THE LIMITS OF THE
DRBIIITMULTIMETER IS DANGEROUS. IT
CAN EXPOSE YOU TO SERIOUS OR
POSSIBLE FATAL INJURY. CAREFULLY
READ AND UNDERSTAND THE CAUTIONS
AND THE SPECIFICATION LIMITS.
²Follow the vehicle manufacturer 's service speci-
fications at all times.
²Do not use the DRBIIItif it has been damaged.
²Do not use the test leads if the insulation is
damaged or if metal is exposed.
²To avoid electrical shock, do not touch the test
leads, tips, or the circuit being tested.
²Choose the proper range and function for the
measurement. Do not try voltage or current mea-
surements that may exceed the rated capacity.
²Do not exceed the limits shown in the table below:
FUNCTION INPUT LIMIT
Volts 0 - 500 peak volts AC
0 - 500 volts DC
Ohms (resistance)* 0 - 1.12 megaohms
Frequency Measured
Frequency Generated0-10kHz
Temperature -58 - +1100ÉF
-50 - +600ÉC
* Ohms cannot be measured if voltage is present.
Ohms can be measured only in a non-powered
circuit.
± Voltage between any terminal and ground
must not exceed 500v DC or 500v peak AC.
± Use caution when measuring voltage above
25v DC or 25v AC.
± Use the low current shunt to measure circuits
up to 10A. Use the high current clamp to
measure circuits exceeding 10A.
± When testing for the presence of voltage or
current, make sure the meter is functioning
correctly. Take a reading of a known voltage or
current before accepting a zero reading.
± When measuring current, connect the meter in
series with test load.
± When using the meter function, keep the
DRBIIItaway from spark plug or coil wires to
avoid measuring error from outside interfer-
ence.
4.3 WARNING
4.3.1 VEHICLE DAMAGE WARNINGS
Before disconnecting any control module, make
sure the ignition is ``off ''. Failure to do so could
damage the module.
When testing voltage or continuity at any control
module, use the terminal side (not the wire end) of
the connector. Do not probe a wire through the
insulation; this will damage it and eventually cause
it to fail because of corrosion.
Be careful when performing electrical tests so as
to prevent accidental shorting of terminals. Such
mistakes can damage fuses or components. Also, a
second code could be set, making diagnosis of the
original problem more difficult.
4.3.2 ROAD TESTING A COMPLAINT
VEHICLE
Some complaints will require a test drive as part
of the repair verification procedure. The purpose of
the test drive is to try to duplicate the diagnostic
code or symptom condition.
CAUTION: Before road testing a vehicle, be
sure that all components are reassembled.
During the test drive, do not try to read the
DRBIIITscreen while in motion. Do not hang
the DRBIIITfrom the rear view mirror or
operate it yourself. Have an assistant
available to operate the DRBIIIT.
4.4 DIAGNOSIS
1. Your diagnostic test procedure must begin with a
thorough visual inspection of the system in ques-
tion for damaged components or disconnected
connectors. For ABS, the brake lamps must be
operational prior to continuing.
2. Connect the DRBIIItto the data link connector
located under the dash. If the DRBIIItdoes not
power up, check the power and ground supplies
to the connector.
3. Select the system in question. Turn the ignition
on. If the DRBIIItdisplays ``No Responseº, refer
to Communication in the Body Diagnostic Pro-
cedures manual to diagnose the symptom.
4. Read and record all diagnostic trouble codes. If
any additional codes are present, proceed to the
appropriate test.
5. For ABS, if there are no diagnostic trouble codes
present, select ``Inputs/Outputs'' and read the
Brake Switch and Brake Lamp Switch inputs as
you press and release the brake pedal. If the
6
GENERAL INFORMATION

INSTALLATION
(1) Position the central timer module in the vehicle
(2) Connect the wire harness connectors to the
central timer module.
(3) Install the screws that secure the central timer
module. Tighten the screws securely.
(4) Route the seat belt latch wire lead through the
hole in the closeout panel and position the panel
beneath the driver seat cushion
(5) Install the screws that secure the closeout
panel beneath the driver seat cushion. Tighten the
screws securely.
(6) Connect the wire harness connector to the seat
belt latch connector.
(7) Slide the driver seat to back to its original posi-
tion.
(8) Reconnect the negative battery cable.
CONTROLLER ANTILOCK
BRAKE
DESCRIPTION
The Controler Antilock Brake (CAB) is mounted to
the Hydraulic Control Unit (HCU) and operates the
ABS system.
REMOVAL
(1) Remove the negative battery cable from the
battery.
(2) Pull up on the CAB harness connector release
and remove connector.
(3) Remove the CAB mounting bolts.
(4) Remove the CAB from the HCU.
INSTALLATION
(1) Install CAB to the HCU.
(2) Install mounting bolts. Tighten to 2 N´m (16 in.
lbs.).
(3) Install the wiring harness connector to the
CAB and push down on the release to secure the con-
nector.
(4) Install negative battery cable to the battery.
ENGINE CONTROL MODULE
DESCRIPTION
The electronic control module (ECM) is mounted to
the left lower dash panel and consists of an electronic
printed circuit board which is designed as a milliliter
board assembly fitted on both sides. The routing of
the wiring harness connector at the ECM connector
are split into interfering cables and sensitive cables
in order to achieve improved electromagnetic compat-
ibility. The smaller wiring harness connector is used
for the vehicle wiring harness and the larger harness
is used for the engine wiring harness. The ECM
stores engine specific data, monitors the connected
sensor and analyzes their measurement (Fig. 2).
Its task consists in controlling the following sys-
tems in line with the analysis of the input signals:
²Fuel Supply System
²Injected Quantity Control
²Emission Control System
²Charge Pressure Control
²Cruise Control
²A/C Compressor Shut-Off
²Pre-Heating Output Relay for the Glow Plugs
²Vehicle Theft
²Air Bag
²Monitors inputs/outputs, checks plausibility and
stores faults
²Share information with other control modules
²Diagnosis
If a sensor should fail, provided the fault is not
serious, the ECM will continue to operate the engine
in Limp-Home Mode (emergency mode) using a
default value for the missing signal. The ECM
ensures that, continuing to operate the engine will
not cause damage or effect safety, otherwise a Engine
shut-off process will be carried out (Fig. 3).Fig. 1 Central Timer Module
1 - DRIVER SEAT
2 - WIRE HARNESS CONNECTOR
3 - SCREW (2)
4 - CLOSEOUT PANEL
5 - CENTRAL TIMER MODULE
6 - WIRE HARNESS CONNECTOR (2)
7 - SCREW (2)
VAELECTRONIC CONTROL MODULES 8E - 3

procedures, further details on wire harness routing
and retention, as well as pin-out and location views
for the various wire harness connectors, splices and
grounds.
The EMIC modules for this model are serviced only
as complete units. The EMIC module cannot be
adjusted or repaired. If a gauge, an LED indicator,
the multi-fuction indicator LCD unit, an electronic
tone generator, the electronic circuit board, the cir-
cuit board hardware, the cluster overlay, the cluster
housing, the cluster hood, the cluster lens, or the
cluster rear cover are damaged or faulty, the entire
EMIC module must be replaced.
OPERATION
The ElectroMechanical Instrument Cluster (EMIC)
is designed to allow the vehicle operator to monitor
the conditions of many of the vehicle components and
operating systems. The gauges, meters and indicators
in the EMIC provide valuable information about the
powertrain, fuel and emissions systems, cooling sys-
tem, lighting systems, safety systems and many
other convenience items. The EMIC is installed in
the instrument panel so that all of these monitors
can be easily viewed by the vehicle operator when
driving, while still allowing relative ease of access for
service. The microprocessor-based EMIC hardware
and software uses various inputs to control the
gauges and indicators visible on the face of the clus-
ter. Some of these inputs are hard wired, but many
are in the form of electronic messages that are trans-
mitted by other electronic modules over the Control-
ler Area Network (CAN) data bus network. (Refer to
8 - ELECTRICAL/ELECTRONIC CONTROL MOD-
ULES/COMMUNICATION - OPERATION).
The EMIC microprocessor smooths the input data
using algorithms to provide gauge readings that are
accurate, stable and responsive to operating condi-
tions. These algorithms are designed to provide
gauge readings during normal operation that are con-
sistent with customer expectations. However, when
abnormal conditions exist such as high coolant tem-
perature, the algorithm can drive the gauge pointer
to an extreme position and the microprocessor can
sound a chime through the on-board audible tone
generator to provide distinct visual and audible indi-
cations of a problem to the vehicle operator. The
instrument cluster circuitry also provides audible
turn signal and hazard warning support by emulat-
ing the ªtickingº sound associated with a conven-
tional electro-mechanical flasher using a contactless
relay. The relay will also provide an indication of a
turn signal failure by sounding at double the usual
frequency. Each audible warning is provided to the
vehicle operator to supplement a visual indication.
The EMIC circuitry operates on battery current
received through a non-switched fused B(+) circuit,
and on a fused ignition switch output circuit. TheEMIC circuitry is grounded through a ground circuit
and take out of the frame wire harness with an eye-
let terminal connector that is secured to a stud by a
nut at a ground location on the dash panel just for-
ward of the instrument cluster. Separate switched
ground inputs from the key-in ignition switch and
the front door jamb switches provide wake-up signals
to the EMIC circuitry. This arrangement allows the
EMIC to provide some features regardless of the igni-
tion switch position, while other features will operate
only with the ignition switch in the On position.
Proper diagnosis and testing of the EMIC, the
CAN data bus, the data bus electronic message
inputs to and outputs from the EMIC, as well as the
retrieval or erasure of a Diagnostic Trouble Code
(DTC) requires the use of a diagnostic scan tool.
Refer to the appropriate diagnostic information. See
the owner's manual in the vehicle glove box for more
information on the features, use and operation of the
EMIC.
GAUGES
All gauges receive battery current through the
EMIC circuitry only when the instrument cluster
detects the ignition switch is in the On position. With
the ignition switch in the Off position, battery cur-
rent is not supplied to any gauges and the EMIC cir-
cuitry is programmed to move all of the gauge
needles back to the low end of their respective scales.
Therefore, the gauges do not accurately indicate any
vehicle condition unless the ignition switch is in the
On position.
All of the EMIC gauges are air core magnetic
units. Two fixed electromagnetic coils are located
within each gauge. These coils are wrapped at right
angles to each other around a movable permanent
magnet. The movable magnet is suspended within
the coils on one end of a pivot shaft, while the gauge
needle is attached to the other end of the shaft. One
of the coils has a fixed current flowing through it to
maintain a constant magnetic field strength. Current
flow through the second coil changes, which causes
changes in its magnetic field strength. The current
flowing through the second coil is changed by the
EMIC circuitry in response to messages received over
the CAN data bus. The gauge needle moves as the
movable permanent magnet aligns itself to the
changing magnetic fields created around it by the
electromagnets.
Proper diagnosis and testing of the gauges, the
CAN data bus and the electronic data bus message
inputs to the EMIC that control each gauge require
the use of a diagnostic scan tool. Refer to the appro-
priate diagnostic information. Specific operation
details for each gauge may be found elsewhere in
this service information.
VAINSTRUMENT CLUSTER 8J - 5

electrical package have a heavy duty 7-way trailer
tow connector installed in a bracket on the trailer
hitch receiver. This package includes a 7-way to
4-way connector adapter unit.
²Trailer Tow Control Module- Vehicles
equipped with a factory-approved, field-installed
trailer towing electrical package have a trailer tow
brake/turn control module located within the driver
side front seat riser that controls the brake lamp and
turn signal lamp outputs to the trailer lighting cir-
cuits.
²Turn Signal Relay- A turn signal relay is
installed in the fuse block located on the underside of
the steering column behind a fuse access panel in the
steering column opening cover on the instrument
panel. The electronic circuitry of the wipers, turn sig-
nals and engine start control module within the fuse
block controls the turn signal relay.
²Wipers, Turn Signals, Engine Start Control
Module- The wipers, turn signals and engine start
control module is integral to the fuse block located on
the underside of the steering column behind a fuse
access panel in the steering column opening cover on
the instrument panel. This module includes active
electronic elements that control the operation of the
turn signal relay based upon inputs from the multi-
function switch and feedback from the turn signal
circuits. (Refer to 8 - ELECTRICAL/POWER DISTRI-
BUTION/FUSE BLOCK - DESCRIPTION).
Hard wired circuitry connects the exterior lighting
system components to the electrical system of the
vehicle. These hard wired circuits are integral to sev-
eral 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 system and to the exterior lighting
system components through the use of a combination
of soldered splices, splice block connectors, and many
different types of wire harness terminal connectors
and insulators. Refer to the appropriate wiring infor-
mation. The wiring information includes wiring dia-
grams, proper wire and connector repair procedures,
further details on wire harness routing and reten-
tion, as well as pin-out and location views for the
various wire harness connectors, splices and grounds.
OPERATION
Following are paragraphs that briefly describe the
operation of each of the major exterior lighting sys-
tems. The hard wired circuits and components of the
exterior lighting systems may be diagnosed and
tested using conventional diagnostic tools and proce-
dures. However, conventional diagnostic methods
may not prove conclusive in the diagnosis of the wip-
ers, turn signals and engine start control module
located within the fuse block underneath the steering
column, the ElectroMechanical Instrument Cluster
(EMIC), the Engine Control Module (ECM), or theController Area Network (CAN) data bus network.
The most reliable, efficient, and accurate means to
diagnose the electronic module within the fuse block,
the EMIC, the ECM, and the CAN data bus network
inputs and outputs related to the various exterior
lighting systems requires the use of a diagnostic scan
tool. Refer to the appropriate diagnostic information.
BACKUP LAMPS
The backup (or reverse) lamps have a path to
ground received at all times through the vehicle wire
harness from a ground point located on the frame
near the left end of the tailgate sill. The backup
lamps receive battery current on the backup lamp
supply circuit only when the backup lamp switch cir-
cuit of the Transmission Range Sensor (TRS) integral
to the gear shifter assembly is closed by the gear
shifter mechanism.
BRAKE LAMPS
The brake (or stop) lamps have a path to ground at
all times through the vehicle wire harness from a
ground point located on the frame near the left end
of the tailgate sill. The Center High Mounted Stop
Lamp (CHMSL) has a path to ground at all times
through the vehicle wire harness from a ground point
on the left side of the dash panel. The brake lamps
and CHMSL receive battery current on the brake
lamp switch output circuit when the brake lamp
switch is closed by the brake pedal arm.
DAYTIME RUNNING LAMPS
Vehicles manufactured for sale in Canada illumi-
nate the low beam headlamp bulb when the engine is
running and the exterior lamps are turned off. This
feature is enabled by the right and left Daytime Run-
ning Lamps (DRL) relays. When the DRL relays are
de-energized, they provide fused battery current from
the circuit K26 relay to the headlamp low beams.
When the headlamps are turned On using the left
(lighting) control stalk of the multi-function switch
the DRL relays are energized, which returns control
of the headlamps to the headlamp switch circuitry of
the multi-function switch. The circuit K26 relay is
energized by the ElectroMechanical Instrument Clus-
ter (EMIC) whenever it receives an electronic mes-
sage from the Engine Control Module (ECM) over the
Controller Area Network (CAN) data bus indicating
that the engine is running. The DRL and circuit K26
relays are installed in a relay bracket located below
the forward edge of the driver side front seat cushion
within the driver side front seat riser.
FRONT FOG LAMPS
Vehicles equipped with optional front fog lamps
have a front fog lamp relay installed in a relay
bracket located below the forward edge of the driver
side front seat cushion within the driver side front
VALAMPS/LIGHTING - EXTERIOR 8L - 3