Page 93 of 4133
43 Seats
Te ch n ica l
data Instruments 
and controlsOperationDrivingInstrument 
cluster displayPractical hints Car care Index Head restraint removal
Removal:
Pull head restraint to its highest position. Push lock 
button (arrow) and pull out head restraint completely 
with both hands.
Installation:
Insert the head restraint and push it down to the stop.
Push lock button (arrow) and adjust head restraint down 
to the desired position.Ensure proper head restraint positioning, see above.
Wa r n i n g !
For your protection, drive only with properly 
positioned head restraints.Adjust head restraint to support the back of the 
head approximately at ear level.Do not drive the vehicle without the seat head 
restraints. Head restraints are intended to help 
reduce injuries during an accident. 
     
        
        Page 94 of 4133
44 Seats
Te ch n ica l
data Instruments 
and controlsOperationDrivingInstrument 
cluster displayPractical hints Car care Index
Heated seats (front, optional on ML 320)
The front seat heater switches are located on the center 
console.
The front seat heaters can be switched on with the 
engine running.Press switch to turn on seat heater:
1Normal seat heating mode. One indicator lamp in 
the switch lights up.
2Rapid seat heating mode. Both indicator lamps in 
the switch light up.
After approximately 5 minutes in the rapid seat 
heating mode, the seat heater automatically 
switches to normal operation and only one indicator 
lamp will stay on.
Turning off seat heater:
If one indicator lamp is on, press upper half of switch.
If both indicator lamps are on, press lower half of 
switch.
If left on, the seat heater automatically turns off after 
approximately 20 minutes of operation.
P54.25-2036-26
12 
     
        
        Page 95 of 4133
45 Seats
Te ch n ica l
data Instruments 
and controlsOperationDrivingInstrument 
cluster displayPractical hints Car care Index Notes:
When in operation, the seat heater consumes a large 
amount of electrical power. It is not advisable to use the 
seat heater longer than necessary.
The seat heaters may automatically switch off if too 
many power consumers are switched on at the same 
time, or if the battery charge is low. When this occurs, 
the indicator lamps in the switch will blink for 
approximately 30 seconds. 
Within this time the seat heaters will switch on again 
automatically as soon as sufficient voltage is available. 
After approximately 30 seconds without sufficient 
voltage the seat heaters switch off (indicator lamps go 
out). 
     
        
        Page 96 of 4133

46 Restraint systems
Te ch n ica l
data Instruments 
and controlsOperationDrivingInstrument 
cluster displayPractical hints Car care Index
Seat belts and integrated restraint system
Your vehicle is equipped with seat belts for all seats, 
emergency tensioning retractors for front and second 
row outboard seat belts, dual front airbags and door 
mounted side impact airbags. Their protective functions 
are designed to complement one another.
Seat belts
Important!
Laws in most states and all Canadian provinces require 
seat belt use.
All states and provinces require use of child restraints 
that comply with U.S. Federal Motor Vehicle Safety 
Standard 213 and Canadian Motor Vehicle Safety 
Standard 213.
All child restraint systems are designed to be secured in 
vehicle seats by lap belts or the lap belt portion of a lap-
shoulder belt.
For your safety and that of your passengers we strongly 
recommend their use.
Wa r n i n g !
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 will result.
According to accident statistics, children are safer 
when properly restrained in the rear seating 
positions than in the front seating positions. 
Infants and small children must ride in back seats 
and be seated in an appropriate infant or child 
restraint system, which is properly secured with 
the vehicle’s seat belt, fully in accordance with the 
child seat manufacturer’s instructions.A child’s risk of serious or fatal injuries is 
significantly increased if the child restraints are 
not properly secured in the vehicle and the child is 
not properly secured in the child restraint. 
     
        
        Page 97 of 4133

47 Restraint systems
Te ch n ica l
data Instruments 
and controlsOperationDrivingInstrument 
cluster displayPractical hints Car care Index Note:
For cleaning and care of the seat belts, see page 282.
Seat belt nonusage warning system
After starting the engine, a warning sounds and the seat 
belt warning lamp< remains illuminated for a short 
time if the driver’s seat belt is not fastened.
Wa r n i n g !
Never ride in a moving vehicle with the backrest 
reclined. Sitting in an excessively reclined position 
can be dangerous. You could slide under the seat 
belt in a collision. If you slide under it, the belt 
would apply force at the abdomen or neck. That 
could cause serious or even fatal injuries. The 
backrest and seat belt provide the best restraint 
when the wearer is in an upright position and the 
belt is properly positioned on the body.
Wa r n i n g !
Failure to wear and properly fasten and position 
your seat belt greatly increases your risk of 
injuries and their likely severity in an accident. 
You and your passengers should always wear seat 
belts.If you are ever in an accident, your injuries can be 
considerably more severe without your seat belt 
properly buckled. Without your seat belt buckled, 
you are much more likely to hit the interior of the 
vehicle or be ejected from it. You can be seriously 
injured or killed.In the same crash, the possibility for injury or 
death is lessened if you are wearing your seat belt.Wa r n i n g !
Never let more people ride in the vehicle than there 
are seat belts available. Be sure everyone riding in 
the vehicle is correctly restrained with a separate 
seat belt. 
     
        
        Page 98 of 4133
48 Restraint systems
Te ch n ica l
data Instruments 
and controlsOperationDrivingInstrument 
cluster displayPractical hints Car care Index
Fastening of seat belts
1Latch plate
2Buckle
3Release buttonPush latch plate (1) into buckle (2) until it clicks. Do not 
twist the belt. A twisted seat belt may cause injury.
To help avoid severe or fatal injuries, the lap belt must 
be positioned as low as possible on your hips and not 
across the abdomen.
Wa r n i n g !
Always fasten your seat belt before driving off. 
Always make sure your passengers are properly 
restrained – even those sitting in the rear. 
     
        
        Page 99 of 4133
49 Restraint systems
Te ch n ica l
data Instruments 
and controlsOperationDrivingInstrument 
cluster displayPractical hints Car care Index Tighten the lap portion to a snug fit by pulling shoulder 
portion up.
The shoulder portion of the seat belt must be pulled 
snug and checked for snugness immediately after 
engaging it.
Adjust seat belt so that shoulder portion is located as 
close as possible to the middle of your shoulder (it 
should not touch the neck). For this purpose, you can 
adjust the height of the belt outlet. Three positions are 
available.4Button for belt outlet height adjustment
To raise, slide belt height adjustment upward.
To lower, press button (4) and slide belt outlet 
downward.
Caution!
For safety reasons, avoid adjusting the seat or backrest 
into positions which could affect the correct seat belt 
positioning. 
     
        
        Page 100 of 4133

50 Restraint systems
Te ch n ica l
data Instruments 
and controlsOperationDrivingInstrument 
cluster displayPractical hints Car care Index
Operation
The inertia reel stops the belt from unwinding during 
sudden vehicle stops or when quickly pulling on the 
belt. The locking function of the reel may be checked by 
quickly pulling out the belt.
Unfastening of seat belts
Push the release button (3) in the belt buckle (2). 
Allow the retractor to completely rewind the seat belt by 
guiding the latch plate (1).
Wa r n i n g !
USE SEAT BELTS PROPERLY.• Seat belts can only work when used properly. 
Never wear seat belts in any other way than as 
described in this section, as that could result 
in serious injuries in case of an accident.• Each occupant should wear their seat belt at all 
times, because seat belts help reduce the 
likelihood of and potential severity of injuries 
in accidents, including rollovers. The 
integrated restraint system includes “SRS” 
(driver airbag, front passenger airbag, front 
and rear door mounted side impact airbags), 
“ETR” (seat belt emergency tensioning 
retractors for the outboard passenger seats 
[except in the optional 3rd row seats]), and 
front seat knee bolsters. The system is 
designed to enhance the protection offered to 
properly belted occupants in certain frontal 
(front airbags) and side (side impact airbags) 
impacts which exceed preset deployment 
thresholds.