2007 MERCEDES-BENZ GL320CDI ESP

203 Controls in detail
Transfer case
Transfer case
LOW RANGE mode*
The LOW RANGE mode is available on vehi-
cles with enhanced off-road package*.
In the following situations you should
switch to LOW RANGE mode:

during off-road driving (page 357)

when crossing water (page 362)

when towing up or down on steep
gradients
With the LOW RANGE selected, the
engine’s power delivery and the shifting
behavior of the automatic transmission are
adjusted. Furthermore, the ABS, ESP
® and
4-ETS functions especially adapted to
off-road travel are activated.
For information on driving safety systems
during LOW RANGE mode, see “Driving
safety systems” (
page 103).
For more information on Off-road driving,
see “Off-road driving” (
page 357).Gear Ranges
There are two possible settings.
!Operational or performance test must only
be conducted on a two-axle dynanometer. If
such tests are necessary, contact an authorized
Mercedes-Benz Light Truck Center. You could
otherwise seriously damage the brake system or
the transfer case which is not covered by the
Mercedes-Benz Limited Warranty.
!Because the ESP® operates automatically,
the engine and ignition must be shut off
(SmartKey in starter switch position0 or1 or
KEYLESS-GO* start/stop button in
position0or1) when testing the parking brake
on a brake test dynamometer and such testing
should be no longer than 10 seconds.
Active braking action through the ESP
® may
otherwise seriously damage the brake system
which is not covered by the Mercedes-Benz
Limited Warranty.
iThe vehicle is equipped with full-time
four-wheel drive. Both the front and rear axles
are powered at all times when the vehicle is
being operated.
HIGH
RANGERoad position for all normal
driving situations.
(LOW RANGE mode off)
LOW
RANGEOff-road position for traveling
on rough terrain.
(LOW RANGE mode on)
Also use the off-road position
when driving on-road on steep
gradients, especially when
towing a trailer.
LOW RANGE acts by raising
the engine’s gear ratio. The ve-
hicle travels at roughly third
the speed compared to when
in the HIGH RANGE position,
leading to an increase in the
engine’s drive power.

206 Controls in detail
Differential locks*
For more information on Off-road driving,
see “Off-road driving” (
page 357).
Vehicles with enhanced off-road package*
are equipped with automatic locks for the
center and rear axle differential to improve
vehicle traction.

The center differential compensates
for differences in wheel rotation be-
tween the front and rear axle.

The rear axle differential compensates
differences between the rear wheels.A few words about differentials and
differential locks*
When a vehicle negotiates a turn, wheels
on the outside of the curve must travel far-
ther and rotate faster than the inside
wheels. The differential, the operation of a
set of gears that allows the powered
wheels in a vehicle to turn at different
speeds, makes this essential function pos-
sible.
The drawback is that the differential also
sends most of the engine’s power to the
wheel with the least load or strain on it. For
example, if one of a vehicle’s powered
wheels sits on a patch of snow and spins
because there is no traction, all of the en-
gine’s power will go to that wheel because
the power will take the path of least resis-
tance. Meanwhile, the opposite wheel, sit-
ting on dry pavement where it could get
enough grip to start the vehicle moving,
sits idle because it receives no power.The Electronic Traction System (ETS) ad-
dresses this problem and provides for
good control and steering ability by auto-
matically slowing the slipping wheel and
thus increasing the power to the other
non-slipping drive wheels to get the vehicle
moving. The ESP
® and ETS in this vehicle
feature such intelligent limited-slip differ-
ential technology, ideally suited for
on-road and light off-road driving. Transfer
case position LOW (
page 203) also en-
hances off-road driving capabilities
(
page 357).
More extreme off-road conditions may call
for another solution, engaging a differen-
tial lock or preventing the differential from
operating altogether. This vehicle comes
with two differential locks: transfer case
(center) and rear. Each can be engaged
simply by operating a rotary switch located
on the center console (
page 207). When
the transfer case (center) differential is
locked, the combined (or average) speed
of the front wheels is identical to the com-
bined rear wheel speed. When the rear
differential is locked, both rear wheels turn
iAt the front axles, the 4-ETS system
(
page 109) compensates for any traction
problems.

207 Controls in detail
Differential locks*
at the same speed, independent of the in-
dividual torque. Please be aware that en-
gaging the differential locks will
significantly reduce the steering ability of
the vehicle.
For your safety and the safety of others
and to prevent damage to the vehicle, the
differential locks must not be engaged
when driving on paved roads. It is impor-
tant to understand that during
on-road/paved driving, differentials are
absolutely necessary for providing the es-
sential control and steering ability of the
vehicle. The differential locks, therefore,
must not be engaged when driving on
paved roads and should only be used to
the extent necessary to negotiate off-road
conditions which cannot be handled by the
systems (automatic 4-ETS, the ESP
®, man-
ual switch position “LOW” of transfer case)
this vehicle comes equipped with.
Switching differential locks*The rotary switch for the differential locks
is located on the upper part of the center
console.
You can select between three locking
modes.
1Rotatable outer adjustment ring with
indicator lamp
2AUTO mode: center differential is auto-
matically locked
3Center differential is completely locked
4Center and rear axle differential are
completely locked
!If the differential locks are engaged, accel-
erate gently when setting the vehicle in motion.
To avoid damage to the transmission, the vehicle
may only be operated on a dynamometer (single
axle dynamometer) if

the axle not being driven is jacked up
or

the associated propeller shaft is disconnect-
ed.

209 Controls in detail
Differential locks*
Start the engine (page 42).
To select the required locking mode,
rotate adjustment ring2 to the
desired position3 or4
(
page 207).
The indicator lamp on the adjustment
ring1 at the respective symbol
comes on.
Example
5Center differential is completely locked
!If the differential locks have been manually
engaged, the tires will scuff on the road surface
when cornering because the differences be-
tween the individual wheel rotation speeds will
not be compensated for.
iThe differential locks are reset to AUTO
mode after the ignition has been switched off for
longer than 10 seconds.

211 Controls in detail
Good visibility
Auto-dimming rear view mirrors*
The reflection brightness of the exterior
rear view mirror on the driver’s side and
the interior rear view mirror will respond
automatically to glare when

the ignition is switched on
and

incoming light from headlamps falls on
the sensor in the interior rear view
mirror
The rear view mirror will not react if

the automatic transmission is set to
positionR

the interior lighting is turned onPower folding exterior rear view
mirrors*
Folding the exterior rear view mirrors
in and out automatically
When the corresponding function in the
control system is activated (
page 185):

The exterior rear view mirrors automat-
ically fold in as soon as the vehicle is
locked from the outside.

The exterior rear view mirrors automat-
ically fold out as soon as the vehicle is
unlocked and the driver’s or front pas-
senger door are subsequently opened.
Warning!G
The auto-dimming function does not react if
incoming light is not aimed directly at sen-
sors in the interior rear view mirror.
The interior rear view mirror and the exterior
rear view mirror on the driver’s side do not
react, for example, when transporting cargo
which covers the rear window.
Light hitting the mirror(s) at certain angles
(incident light) could blind you. As a result,
you may not be able to observe traffic con-
ditions and could cause an accident.
Warning!G
Exercise care when using the passen-
ger-side exterior rear view mirror. The mirror
surface is convex (outwardly curved surface
for a wider field of view). Objects in mirror
are closer than they appear. Check your
interior rear view mirror or glance over your
shoulder before changing lanes.
!Before you drive the vehicle through an
automatic car wash, fold the exterior rear view
mirrors in. Otherwise they may get damaged.

215 Controls in detail
Good visibility
Rear window defroster
The rear window defroster uses a large
amount of power. To keep battery drain to
a minimum, switch off the defroster as
soon as the rear window is clear. The de-
froster is automatically deactivated after
approximately 6 to 17 minutes of
operation depending on the outside tem-
perature.
Switch on the ignition (page 42).Activating
Press button1 on the climate con-
trol panel (
page 218) or the automat-
ic climate control* panel (
page 232).
The indicator lamp on the button
comes on.
Deactivating
Press button1 once more.
The indicator lamp on the button goes
out.
Warning!G
Any accumulation of snow and ice should be
removed from the rear window before driv-
ing. Visibility could otherwise be impaired,
endangering you and others.!If the rear window defroster switches off too
soon and the indicator lamp starts flashing, too
many electrical consumers are operating simul-
taneously and there is insufficient voltage in the
battery. The system responds automatically by
switching the rear window defroster off.
As soon as the battery has sufficient voltage, the
rear window defroster switches back on auto-
matically.

222 Controls in detail
Climate control
Adjusting air volume
Five blower speeds are available.
Press button
to decrease or
buttonQ to increase air volume
(
page 218) to the desired level.
The indicator lamp on buttonU
(
page 218) goes out. The automatic
operation of air volume switches off.
The selected blower speed is shown in
the air volume displayb
(
page 218).
Adjusting air volume for the center and
side air vents
Opening the center air vents
Turn thumbwheels4 and7
(
page 216) to the right.
The corresponding center air vents on
the left and right are open.Closing the center air vents
Turn thumbwheels4 and7
(
page 216) to the left.
The corresponding center air vents on
the left and right are closed.
Opening the side air vents
Turn thumbwheels3 and8
(
page 216) to the right.
The corresponding side air vents on the
left and right are open.
Closing the side air vents
Turn thumbwheels3 and8
(
page 216) to the left.
The corresponding side air vents on the
left and right are closed.Air vents in the roof liner over the
second-row seats*
1Thumbwheel for air volume control
2Air vent, adjustable
Adjusting air volume
Turn thumbwheel1 d o w n t o d e c r e a s e
the air volume.
or
Turn thumbwheel1 u p t o i n c r e a s e t h e
air volume.

225 Controls in detail
Climate control
Activating
Press button: (page 218).
The indicator lamp on the button
comes on.DeactivatingPress button:.
The indicator lamp on the button goes
out.Air recirculation mode with conve-
nience closing and opening feature
iThe air recirculation mode is activated auto-
matically at high outside temperatures.
The indicator lamp on button: is not lit when
the air recirculation mode is switched on auto-
matically.
A quantity outside air is added after
approximately 30 minutes.
If you have turned off the air conditioning
(
page 226) or the outside temperature is
below 41°F (5°C), the air recirculation mode will
not switch on automatically.
iTo cool the interior as fast as possible, the
climate control automatically switches to air
recirculation. The indicator lamp on button:
is not lit when the air recirculation mode has
been switched on automatically.
iThe air recirculation mode is deactivated
automatically

after 5 minutes if the outside temperature is
below approximately 41°F (5°C)

after 5 minutes if the air conditioning and
air-drying is turned off

after 30 minutes if the outside temperature
is above approximately 41°F (5°C)
Warning!G
Never operate the windows and tilt/sliding
sunroof* if there is the possibility of anyone
being harmed by the opening or closing pro-
cedure.
When using the air recirculation mode with
convenience closing feature, should the up-
ward movement of a window be blocked by
some obstruction including but not limited
to arms, hands, fingers, etc., the automatic
reversal feature will not operate.
In case the procedure causes potential
danger:
Vehicles with or without tilt/sliding sun-
roof*: The closing of the windows can be im-
mediately halted by pressing or pulling the
respective window switch. The closing of the
tilt/sliding sunroof* can be immediately
halted by moving the switch for the tilt/slid-
ing sunroof* in any direction.