Hummer 2007 H3 - Manual (Page 112)

Notice: Operating your vehicle in
Four-Wheel-Low Lock above 30 mph (48 km/h)
for any extended period of time could cause
damage to the transfer case. Do not operate
your vehicle in Four-Wheel-Low Lock above
30 mph (48 km/h) for extended periods.
4 n Q (Four-Wheel-Low Lock): This mode
delivers extra torque to all four wheels and is used
for extreme off-road conditions. You might
choose 4-Wheel-Low Lock if you are driving in
off-road situations, such as, deep sand, mud, or
snow and climbing or descending steep hills.
If the vehicle has a locking rear axle, when in this
mode you can also choose to lock the rear
axle for additional traction in extreme off-road
situations. See Locking Rear Axle on page 243.
Indicator lights in the buttons show which
mode you are in. The indicator lights will come on
briefly when you turn on the ignition the mode
the vehicle is in will stay on. If the lights do
not come on, you should take your vehicle to
your dealer for service. An indicator light
will flash while shifting the transfer case.
It will remain lit when the shift is complete.
If for some reason the transfer case cannot
make a requested shift, it will return to the
last chosen setting.
If the SERV 4WD message on the Driver
Information Center (DIC) stays on, you should
take your vehicle to your dealer for service. See
Service 4WD message under DIC Warnings
and Messages on page 196.
Shifting between Four-Wheel High and
Four-Wheel-High Lock
With the vehicle traveling less than 45 mph
(72 km/h), press and release the Four-Wheel High
or Four-Wheel-High Lock button. The indicator
light will flash while shifting. It will remain lit when
the shift is complete.
It may be necessary to drive backwards while
turning for a distance of 25 feet (7.5 m) to get the
lock feature to disengage.
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