1997 MERCEDES-BENZ ML350 lock

Fig. 1: Locating Restraint System Components (E Class Shown; Others Are Similar)
Courtesy of MERCEDES-BENZ OF NORTH AMERICA
Both SRS and ETR are electronically activated by a single control unit if a moderately severe to severe frontal
collision occurs. There are 2 thresholds which must be exceeded to trigger an ETR action, air bag deployment,
or both. If a moderately severe frontal collision occurs exceeding first triggering threshold where protection
from safety belt is sufficient, only Emergency Tensioning Retractor (ETR) is activated if safety belt is buckled.
If a moderately severe frontal collision occurs exceeding first triggering threshold where protection from safety
belt is sufficient, but safety belt is not buckled, air bag is deployed and EAR is not activated.
If a severe frontal collision occurs exceeding second triggering threshold where protection from safety belt is
insufficient, air bag is deployed. EAR is activated if safety belt is buckled. If safety belt is not buckled, ETR is
not activated when second triggering threshold is reached. Passenger air bag will deploy even if passenger seat
is not occupied when a triggering threshold is exceeded. If during a severe frontal collision the power supply is
interrupted, the driver and passenger air bag can still be deployed, but ETR cannot be activated.
The side air bag on the driver-side deploys whenever the driver-side air bag module is deployed and when there
is a substantial side impact crash. The air bag on the passenger-side will activate only when a sensor (Occupied
Seat Recognition Sensor) in the passenger seat sends a signal to the control module that the passenger-side seat
is occupied. During a collision, the side air bag will then deploy.
SERVICING
SRS AIR BAG label on driver-side door latch post indicates SRS replacement date for driver and passenger air
bag units. All SRS components must be thoroughly inspected, including wiring harness. Before component
replacement, check for SRS fault codes by performing system operation check. See SYSTEM OPERATION
CHECK . SRS service life is 10 years from manufactured date, or 10 years from SRS replacement date after
accident related repairs are completed.
POST-COLLISION INSPECTION
When a vehicle has been involved in a collision, certain components of the passive restraint system must be
inspected or replaced. See PASSIVE RESTRAINT SYSTEM INSPECTION article in the GENERAL
INFORMATION section for post-collision inspection information.
ADJUSTMENTS
If fixing screws were not used during clockspring removal or clockspring was rotated during removal, turn
clockspring clockwise until resistance is detectable. Turn clockspring counterclockwise 2-2.5 turns until fixing
screws can be unscrewed holding clockspring in this position.
DISPOSAL PROCEDURES
WARNING:An undeployed air bag module or ETR should never be disposed of
without first being deployed. See SCRAPPED VEHICLE
. If deployment is
not possible, contact vehicle manufacturer for further instructions.

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UNDEPLOYED AIR BAG/ETR
After deploying procedures and/or diagnostic testing have confirmed air bag module and/or ETR is
undeployable, contact vehicle manufacturer for proper disposal instructions.
REMOVAL & INSTALLATION
CLOCKSPRING ASSEMBLY
Removal & Installation
1. Before proceeding, see SERVICE PRECAUTIONS . Disable air bag system. See DISABLING &
ACTIVATING AIR BAG SYSTEM .
2. Remove driver air bag module. See DRIVER
-SIDE AIR BAG MODULE . Remove steering wheel bolt.
Using a puller, remove steering wheel. Disconnect lower clockspring connector. Turn 2 fixing screws
(locating on clockspring) counterclockwise until clockspring cannot be rotated. Remove clockspring
mounting screws as necessary. Disconnect all necessary electrical connectors. Remove clockspring
assembly. To install, reverse removal procedure. Activate air bag system. See DISABLING &
ACTIVATING AIR BAG SYSTEM . Perform system operation check to ensure system is functioning
properly. See SYSTEM OPERATION CHECK
.
CONTROL UNIT
Removal & Installation (C Class)
1. Before proceeding, see SERVICE PRECAUTIONS . Disable air bag system. See DISABLING &
ACTIVATING AIR BAG SYSTEM . Remove ignition key. Remove shift lever cover bezel. Lift shift
lever cover enough to disconnect electrical connector. Remove shift lever cover.
2. Remove storage compartment mounting screws from center console. Remove storage compartment.
Remove ashtray. Disconnect electrical connectors as necessary. Disconnect control module electrical
connector. Remove control module mounting bolts. Remove control module.
3. To install, reverse removal procedure. Ensure control module arrow points to front of vehicle. Set
parameters and program new control module with Hand-Held Tester (965 589 00 01 00). Activate air bag
system. Perform system operation check to ensure system is functioning properly. See SYSTEM
OPERATION CHECK .
Removal & Installation (E Class)
1. Before proceeding, see SERVICE PRECAUTIONS . Disable air bag system. See DISABLING &
ACTIVATING AIR BAG SYSTEM . Remove ignition key. Remove gear shift cover panel. Remove
ashtray and ashtray housing at front of console. Remove radio (if necessary).
2. Remove center console right side cover screws and right side cover. Disconnect electrical connector for
control unit. Remove 2 control unit mounting screws. Remove control unit. WARNING:Failure to follow service precautions may result in air bag deployment and
personal injury. See SERVICE PRECAUTIONS
. After component
replacement, check system operation. See SYSTEM OPERATION CHECK
.

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Fig. 3: Removing Side Air Bag Sensor (E Class Shown; Others Are Similar)
Courtesy of MERCEDES-BENZ OF NORTH AMERICA
OCCUPIED SEAT RECOGNITION SENSOR
Removal & Installation
1. Before proceeding, see SERVICE PRECAUTIONS . Disable air bag system. See DISABLING &
ACTIVATING AIR BAG SYSTEM .
2. Remove cover on front seat cushion. Remove ignition key. Unclip connection for occupied seat
recognition sensor on seat connector block. Remove electrical connection lead from seat and pull upward
out of rubberized fiber matting. See Fig. 4
.
3. To install, lay out occupied seat recognition sensor uniformly on rubberized fiber matting. Fabric side
should point upward. Do not kink occupied seat sensor. Reverse removal procedure. Perform system
operation check to ensure s
ystem is functioning properly. See SYSTEM OPERATION CHECK.

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passenger-side air bag module squib connector. Remove 4 passenger-side air bag module mounting nuts.
2. To install, reverse removal procedure. Ensure passenger-side air bag module squib connector audibly
clicks when connecting connector. Activate air bag system. Perform system operation check to ensure
system is functioning properly. See SYSTEM OPERATION CHECK
.
Removal & Installation (E Class)
1. Before proceeding, see SERVICE PRECAUTIONS . Disable air bag system. See DISABLING &
ACTIVATING AIR BAG SYSTEM . Remove ignition key. Remove 2 central mounting bolts for
passenger-side air bag module. Lift air bag module enough to unplug connector from rear of module.
Place module away from work area, with pad facing upward.
2. If necessary to replace passenger air bag installation frame, remove 4 frame mounting bolts. Remove
installation frame from vehicle.
3. To install air bag module or installation frame, reverse removal procedure. Activate air bag system.
Perform system operation check to ensure system is functioning properly. See SYSTEM OPERATION
CHECK .
Removal & Installation (S Class)
1. Before proceeding, see SERVICE PRECAUTIONS . Disable air bag system. See DISABLING &
ACTIVATING AIR BAG SYSTEM . Remove ignition key. Open glove box door. Remove 4 clips
securing glove box. Remove glove box compartment. When removing compartment, disconnect glove
box light. Remove glove box door lock striker.
2. Disconnect passenger-side air bag module squib connector. Remove 4 passenger-side air bag module
mounting nuts. Remove passenger-side air bag module through glove box opening. Place module away
from work area with pad facing up.
3. To install, reverse removal procedure. Ensure module squib connector audibly clicks when connecting
connector. Activate air bag system. Perform system operation check to ensure system is functioning
properly. See SYSTEM OPERATION CHECK
.
Removal & Installation (SL Class)
1. Before proceeding, see SERVICE PRECAUTIONS . Disable air bag system. See DISABLING &
ACTIVATING AIR BAG SYSTEM . Remove ignition key. Remove cover below instrument panel.
Remove one bolt in installation slot of center air outlet, and one bolt below right air outlet.
2. Remove air bag panel (3 Phillips screws and 2 hex bolts). Unplug connector at squib of passenger-side air
bag unit. Remove mounting bolts. Pull off and take air bag out of panel opening.
3. To install air bag module, reverse removal procedure. Activate air bag system. Perform system operation
check to ensure system is functioning properly. See SYSTEM OPERATION CHECK
.
Removal & Installation (CLK 320)
1. Before proceeding, see SERVICE PRECAUTIONS . Disable air bag system. See DISABLING &
ACTIVATING AIR BAG SYSTEM . Remove ignition key. Remove instrument panel. Disconnect
passenger-side air bag module connector. Remove 4 screws and passenger-side air bag module.
2. To install air ba
g module, reverse removal procedure. Activate air bag system. Perform system operation

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If any part of SRS wiring harness is damaged, DO NOT repair wiring harness, replace complete wiring harness.
TORQUE SPECIFICATIONS
TORQUE SPECIFICATIONS
(1)
DIAGNOSIS & TESTING
Before proceeding, see SERVICE PRECAUTIONS
. The control module is capable of diagnosing airbag
system components and ETR components. If a fault is detected by the control module or system is
malfunctioning, SRS warning light will do one or more of the following:
SRS warning light goes out after 2 minutes. System fault is noted, however occupant protection is not
affected. See RETRIEVING FAULT CODES
.
SRS warning light illuminates continuously. System is faulty which may result in a non deployment or
false deployment. See RETRIEVING FAULT CODES
.
SRS warning light blinks continuously. Control module has been replaced without setting control module
parameters.
RETRIEVING FAULT CODES
1. Check vehicle fuses. Replace any blown fuses as necessary. Ensure vehicle battery voltage is 11 volts or
more. Ensure SRS warning light functions. Turn ignition off. Connect Hand-Held Tester (HHT) (965 589
00 01) to Data Link Connector (DLC).
2. DLC is located in right rear corner of engine compartment. It may be necessary to use Adapter (965 589
00 40 or 965 589 00 50) to connect HHT to DLC. After HHT displays module number and version, press
return key to start diagnosis. Using HHT, follow HHT prompts to retrieve SRS fault codes.
3. HHT will display a 3 digit fault code, and may display additional graphic information. This additional
graphic information will help in diagnosis of fault code. See Fig. 6
. During diagnosis HHT will display 4
different graphic displays informing technician if a test passes or fails, or if seat belt buckle is latched or
not latched. See Fig. 6
.
4. These
graphic displays are displayed as applicable by HHT during testing. See FAULT CODES table.
ApplicationFt. Lbs. (N.m)
Steering Wheel Hub Bolt52-66 (70-90)
INCH Lbs. (N.m)
Driver Air Bag Module Bolts (Torx)44-62 (5-7)
(1)Torque specifications are not available for clockspring assembly, control module or passenger-side
air bag module.
NOTE: After component replacement, perform a system operation check to ensure
proper system operation. See SYSTEM OPERATION CHECK
.
NOTE: Fault codes may only be retrieved using Hand-Held Tester (965 589 00 01) and
Adapter (965 589 00 40 or 965 589 00 50).

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with HHT connected to DLC and ignition key removed. Remove driver-side air bag module. Disconnect
driver-side air bag module squib connector R12/3. Connect Resistance Substitution Unit (124 589 09 63)
to driver-side air bag module squib connector (harness side). Set resistance substitution unit to 2 ohms.
Turn ignition key to position "2". Read NOMINAL VALUE/HHT DISPLAY column. If HHT displays a
check, replace driver-side air bag module. If HHT displays an "F", go to step 3.2.
Read TEST CONNECTION (NOT FOR HHT) column. Horn/air bag clockspring connector A45x1,
terminals No. 1 and 2 are identified. Read TEST CONDITION column. Test circuit with HHT connected
to DLC. Remove ignition key. Connect Resistance Substitution Unit (124 589 09 63 00) to horn/air bag
clockspring connector A45x1. Set resistance substitution unit to 2 ohms. Read NOMINAL VALUE/HHT
DISPLAY column. If HHT displays a check, check horn/air bag clockspring for continuity. Replace
horn/air bag clockspring as necessary. If HHT displays an "F", go to step 3.4.
MODEL IDENTIFICATION
COMPONENT IDENTIFICATION
DIAGNOSTIC TESTS NOTE: Some testing is identified by model number. To identify models by model
number see MODEL IDENTIFICATION
table.
Model NumberModel
129SL Class
140S Class
170SLK 230
202C Class
208CLK 320
210E Class
ComponentManufacturer's Designation
A45Horn/Air Bag Clockspring
A53Driver-Side Air Bag Sensor
A54Passenger-Side Air Bag Sensor
B41/1Passenger-Side Seat Occupied Recognition Sensor
N2/2Control Module
R12/1Driver-Side ETR Squib Connector
R12/2Passenger-Side ETR Squib Connector
R12/3Driver-Side Air Bag Squib Connector
R12/8Passenger-Side Air Bag Squib Connector
R12/9Side Air Bag (Driver-Side)Squib Connector
R12/10Side Air Bag (Passenger-Side) Squib Connector
S68/3Driver-Side Belt Buckle Switch
S68/4Passenger-Side Belt Buckle Switch
W26Control Module Ground
X11/4Data Link Connector

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1 Contents
IntroductionProduct information .......................... 7
Roadside assistance ......................... 10
Where to find it ................................ 14
Reporting Safety Defects ................ 16Instruments and controlsInstruments and controls ............... 18
Center console .............................. 20
Overhead control panel ............... 21OperationVehicle keys ...................................... 24
Start lock-out .................................... 25
General notes on the
central locking system ............... 26
Central locking system ................... 26
Radio frequency
remote control .............................. 26
Unlocking the liftgate .................. 28
Panic button .................................. 28
Mechanical keys ........................... 29Doors ................................................. 30
Central locking switch .................... 32
Automatic central locking .......... 32
Emergency unlocking in case
of accident ................................... 33
Liftgate .............................................. 34
Antitheft alarm system ................... 35
Tow-away alarm and
glass breakage sensor ............... 36
Seats, front ....................................... 37
Manual seats ................................ 39
Power seats ................................... 40
Head restraint ...............................41
Heated seats ..................................... 44
Seat belts and integrated
restraint system .......................... 46
Seat belts .......................................... 46
Seat belt nonusage
warning system ............................ 47
BabySmart
TM airbag
deactivation system ................... 53
Self-test BabySmart
TM
without special child
seat installed ................................ 53Supplemental restraint
system (SRS) ................................ 54
Emergency tensioning
retractor (ETR) ............................. 55
Airbags .............................................. 56
Safety guidelines for the
seat belt, emergency
tensioning retractor
and airbag ..................................... 63
Infant and child
restraint systems .......................... 65
Adjustable steering wheel .............. 70
Inside rear view mirror .................. 71
Antiglare night position .............. 71
Exterior rear view mirrors ............. 73
Exterior rear view mirror,
electrically folding ....................... 75
Instrument cluster ........................... 76
Indicator lamps in the
instrument cluster ...................... 78
Trip computer ................................... 83
Flexible service system (FSS) ........ 87
Engine oil level indicator ................ 89
Exterior lamp switch ....................... 90

2 Contents
Fog lamp switch
(except Canada) ........................... 92
Fog lamp switch
(Canada only) .............................. 93
Hazard warning flasher
switch ............................................ 94
Headlamp cleaning system ............ 94
Windshield wiper/washer
switch ............................................ 95
Rear window wiper/washer ........... 96
Climate control ................................. 98
Basic setting – Heater ............... 100
Basic setting –
Air conditioner ........................... 100
Special setting ............................ 101
Dust filter .................................... 102
Air recirculation ......................... 102
Rear window defroster .............. 103
Power windows ............................... 104
Rear quarter windows ................... 106
Sliding/pop-up roof ....................... 107
Skyview Top .................................... 109
Interior lighting ..............................110
Sun visors ........................................113Illuminated vanity mirrors ........... 113
Interior ............................................. 114
Storage compartments,
armrest and cup holder ............ 114
Glove box ...................................... 115
Armrest in rear bench seat ........... 117
Ashtrays ........................................... 118
Lighter .............................................. 119
Split rear seat bench ..................... 120
Easy entry/exit feature ............. 123
Rear seat head restraints ......... 124
Third row seats .............................. 126
Removable cargo floor plates ...... 129
Enlarged cargo area .......................131
Cargo tie-down rings .....................132
Hooks ...............................................133
Partition net ....................................133
Loading instructions ......................136
Cargo area cover blind ..................137
Telephone, general .........................139
Cellular telephone ..........................139
Garage door opener ....................... 140
DrivingControl and operation of
radio transmitters ..................... 146
The first 1 000 miles
(1 500 km) ................................. 147
Maintenance ................................... 147
Tele Aid ........................................... 148
Catalytic converter ........................ 160
Emission control ............................ 161
Steering lock ................................... 162
Starting and turning off
the engine .................................. 164
Automatic transmission ............... 165
Parking brake ................................. 173
Driving instructions ...................... 174
Drive sensibly – save fuel ......... 174
Drinking and driving ................. 174
Pedals ........................................... 174
Power assistance ........................ 175
Brakes .......................................... 175
Driving off ................................... 176
Parking ........................................ 176
Tires ............................................. 177