MERCEDES-BENZ ML350 1997 Complete Repair Manual

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Supplemental restraint system (SRS)
Airbags are intended as a supplement to seat belts.
Airbags alone cannot protect as well as airbags plus
seat belts in impacts for which the airbags were
designed to operate, and do not afford any protection
whatsoever in crashes for which the airbags are not
designed to deploy.
The SRS uses two crash severity levels (thresholds) to
activate either the Emergency Tensioning Retractor
(ETR) or front airbag or both. Activation depends on the
direction and severity of the impact exceeding the
preset thresholds and whether the seat belt is fastened. Seat belt fastened
• first threshold exceeded: ETR activates
• second threshold exceeded: airbag also activates
Seat belt not fastened
Front seats: • first threshold exceeded:
airbag activates, but not ETR
Rear outer seats: • first threshold exceeded:
ETR activates
Driver, front passenger and rear outer seat systems
operate independently of each other.

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Emergency tensioning retractor (ETR)
The seat belts for the outboard passenger seats (except
in the optional 3rd row seats) are equipped with
emergency tensioning retractors. These tensioning
retractors are located in each belt’s inertia reel and
become operationally ready with the key in steering
lock position 1 or 2.
The emergency tensioning retractors are designed to
activate only when the seat belts are fastened during
frontal impacts exceeding the first threshold of the SRS
and in rear impacts exceeding a preset severity level.
They remove slack from the belts in such a way that the
seat belts fit more snugly against the body restricting its
forward movement as much as possible. In cases of other frontal impacts, angled impacts, roll-
overs, certain side impacts, or other accidents without
sufficient frontal or rear impact forces, the emergency
tensioning retractors will not be activated. The driver
and passengers will then be protected by the fastened
seat belts and inertia reel in the usual manner.
For seat belt and emergency tensioning retractor see
page 63.

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Airbags
1 Driver airbag
The most effective occupant restraint system yet
developed for use in production vehicles is the seat belt.
In some cases, however, the protective effect of a seat
belt can be further enhanced by an airbag.
The driver airbag is located in the steering wheel hub. 2
Front passenger airbag
The passenger front airbag is located in the dashboard
ahead of the front passenger.

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3
Side impact airbag, front
The side impact airbags are located in the front and rear
doors.
In conjunction with wearing the seat belts, the driver
and front passenger airbags can provide increased
protection for the driver and front passenger in certain
frontal impacts exceeding preset thresholds. 4
Side impact airbag, rear
Door mounted side impact airbags can provide
increased protection to belted outboard occupants on
the impacted side of the vehicle in side impacts
exceeding its preset threshold.
Important!
The operational readiness of the airbag system is
verified by the indicator lamp “SRS” in the instrument
cluster when turning the key in steering lock to
position 1 or 2. If no fault is detected, the lamp will go
3

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out after approximately 5 seconds; after the lamp goes
out, the system continues to monitor the components
and circuitry of the airbag system and will indicate a
malfunction by coming on again. If the lamp does not
come on at all or if it fails to extinguish after
approximately 5 seconds or if it comes on thereafter,
a malfunction in the system has been detected.
The following system components are monitored or
undergo a self-check: crash-sensor(s), airbag ignition
circuits, front seat belt buckles, emergency tensioning
retractors, seat sensor.
Initially, when the key is turned from steering lock
position 0 to positions 1 or 2, malfunctions in the
crash-sensor are detected and indicated (the “SRS”
indicator lamp stays on longer than 5 seconds or does
not come on).
Have the system checked at your authorized
Mercedes-Benz Light Truck Center immediately. In the operational mode, after the indicator lamp has
gone out following the initial check, interruptions or
short circuits in the airbag ignition circuit and in the
driver and front passenger seat belt buckle harnesses,
and low voltage in the entire system are detected and
indicated.
Wa r n i n g !
In the event a malfunction of the “SRS” is indicated
as outlined above, the “SRS” may not be
operational. For your safety, we strongly
recommend that you visit an authorized
Mercedes-Benz Light Truck Center immediately to
have the system checked; otherwise the “SRS” may
not be activated when needed in an accident, which
could result in serious or fatal injury, or it might
deploy unexpectedly and unnecessarily which
could also result in injury.

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Front airbags
The driver and front passenger front airbags are
designed to activate only in certain frontal impacts
exceeding a preset threshold.
The front passenger airbag deploys only if the front
passenger seat is occupied and the ü indicator lamp
in the instrument cluster is not illuminated.
Note:
Heavy objects on the front passenger seat can appear to
the “SRS” to indicate the presence of an occupant in
that seat which causes the passenger front airbag to
deploy in a crash exceeding the appropriate threshold.
Side impact airbags
The side impact airbags are designed to activate only in
certain side impacts exceeding a preset threshold. Only
the side impact airbags on the impacted side of the
vehicle deploy.
The side impact airbag for the front passenger deploys
only if the front passenger seat is occupied.
Side impact airbags operate best in conjunction with a
properly positioned and fastened seat belt. Note:
Heavy objects on front passenger seat can cause the
side impact airbag to deploy in a crash.
Important!
Airbags are designed to activate only in certain
frontal (front airbags) impacts, or side (side impact
airbags) impacts which exceed preset thresholds.
Only during these types of impacts, if of sufficient
severity to meet the deployment thresholds, will
they provide their supplemental protection.
The driver and passenger should always wear their
seat belts, otherwise it is not possible for the airbags
to provide their intended supplemental protection.
In cases of other frontal impacts, angled impacts,
roll-overs, other side impacts, rear collisions, or
other accidents in which the airbags are not
designed to deploy, the airbags will not be activated.
The driver and passenger will then be protected by
the fastened seat belts.
We caution you not to rely on the presence of the
airbags in order to avoid wearing your seat belt.

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Your vehicle was originally equipped with airbags
which are designed to activate in certain impacts
exceeding a preset threshold to reduce the potential
and severity of injury. It is important to your safety
and that of your passenger that you replace deployed
airbags and repair any malfunctioning airbags to
ensure the vehicle will continue to provide crash
protection for occupants.
Wa r n i n g !
Airbags are designed to reduce the potential of
injury in certain frontal (front airbags) impacts,
and side (side impact airbags) impacts which may
cause significant injuries, however, no system
available today can totally eliminate injuries and
fatalities.The activation of the “SRS” temporarily releases a
small amount of dust from the airbags. This dust,
however, is neither injurious to your health, nor
does it indicate a fire in the vehicle. The dust might
cause some temporary breathing difficulty for
people with asthma or other breathing trouble. To
avoid this, you may wish to get out of the vehicle as
soon as it is safe to do so. If you have any breathing
difficulty but cannot get out of the vehicle after the
airbag inflates, then get fresh air by opening a
window or door.
Wa r n i n g !
To reduce the risk of injury when the front airbags
inflate, it is very important for the driver and front
passenger to always be in a properly seated
position and to wear their seat belts.For maximum protection in the event of a collision
always be in normal seated position with your back
against the backrest. Fasten your seat belt and
ensure that it is properly positioned on your body.Since the airbag inflates with considerable speed
and force, a proper seating and hands on steering
wheel position will help to keep you at a safe
distance from the airbag. Occupants who are
unbelted, out of position or too close to the airbag
can be seriously injured by an airbag as it inflates
with great force in the blink of an eye:

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• Sit properly belted in an upright position with
your back against the backrest.• Adjust the driver’s seat as far as possible
rearward, still permitting proper operation of
vehicle controls. The distance from the center
of the driver’s breastbone to the center of the
airbag cover on the steering wheel must be at
least ten inches (25 cm) or more. You should be
able to accomplish this by a combination of
adjustments to the seat and steering wheel. If
you have any problems, please see your
authorized Mercedes-Benz Light Truck Center.• Do not lean with your head or chest close to the steering wheel or dashboard.• Keep hands on the outside of steering wheel rim. Placing hands and arms inside the rim
can increase the risk and potential severity of
hand / arm injury when the driver front airbag
inflates.• Adjust the front passenger seat as far as possible rearward from the dashboard when
the seat is occupied.
• Occupants, especially children, should never lean their heads in the area of the door where
the side airbag inflates. This could result in
serious injuries or death should the airbag be
triggered. Always sit upright, properly use the
seatbelts and appropriate size infant or child
restraint system.• Children 12 years old and under must never ride in the front seat, except in a
Mercedes-Benz authorized BabySmart
TM
compatible child seat, which operates with the
BabySmart
TM system installed in the vehicle to
deactivate the passenger side front airbag
when it is properly installed. Otherwise they
will be struck by the airbag when it inflates in
a crash. If this happens, serious or fatal injury
can result.
Failure to follow these instructions can result in
severe or fatal injuries to you or other occupants.

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Wa r n i n g !
Accident research shows that the safest place for
children in an automobile is in the rear seat.
Should you choose to place a child 12 years old or
under in the front passenger seat of your vehicle,
you must properly use a BabySmart
TM child
restraint which will turn off the passenger side
front airbag. BabySmart
TM will not, however, turn
off the vehicle’s side impact airbag.
It should be noted that with respect to both front
and rear side impact airbags there is a possibility
for a side airbag related injury if occupants,
especially children, are not properly seated or
restrained when next to a side airbag which needs
to deploy rapidly in a side impact in order to do its
job.
To help avoid the possibility of injury, please follow
these guidelines: (1) occupants, especially
children, should never place their bodies or lean
their heads in the area of the door where the side
airbag inflates. This could result in serious
injuries or death should the side airbag be
activated; (2) always sit upright, properly use the
seat belts and use an appropriately sized infant or
child restraint system for all children 12 years old
or under; and (3) always wear seat belts properly.If you believe that, even with the use of these
guidelines, it would be safer for your rear seat
occupants to have both rear door mounted side
airbags deactivated, then deactivation can be
accomplished upon your written election to do so at
your authorized Mercedes-Benz Center at an
additional cost. Please contact your local
authorized Mercedes-Benz Center or call our Client
Assistance Center at 1-800-FOR-MERCedes
(1-800-367-6372) for details.

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Safety guidelines for the seat belt,
emergency tensioning retractor and airbag
Wa r n i n g !
• Damaged seat belts or belts that were highly stressed in an accident must be replaced and
their anchoring points must also be checked.
Use only belts installed or supplied by an
authorized Mercedes-Benz Light Truck Center.• Do not pass belts over sharp edges.• Do not make any modification that could change the effectiveness of the belts.• Airbags and ETR’s are designed to function on a one-time-only basis. An airbag or emergency
tensioning retractor (ETR) that was activated
must be replaced.
• An airbag system component within the steering wheel gets hot after the airbag has
inflated. Do not touch.• Improper work on the system, including incorrect installation and removal, can lead to
possible injury through an unintended
activation of the “SRS”.• No modifications of any kind may be made to any components or wiring of the “SRS”. This
includes changing or removing any component
or part of the “SRS”, the installation of
additional trim material, badges etc. over the
steering wheel hub, front passenger airbag
cover, or front door trim panels, and
installation of additional electrical / electronic
equipment on or near “SRS” components and
wiring. Keep area between airbags and
occupants free of objects (e.g. packages,
purses, umbrellas, etc.).