Hummer 2006 H2 - Manual (Page 108)

Indicator lights in the buttons show which mode you are
in. The indicator lights will come on briefly when you
turn on the ignition and one 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 on 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 SERVICE 4WD message stays on, you should
take your vehicle to your dealer for service. See “Service
4WD message” under Driver Information Center (DIC)
on page 3-45.
Shifting between Four-Wheel High and
Four-Wheel-High Lock
With the vehicle traveling less than 40 mph (64 km/h),
press and release the Four-Wheel High or
Four-Wheel-Low Lock button. The indicator light will
flash while shifting. It will remain on when the shift
is complete.
It may be necessary to drive backwards for a short
distance of 25 feet (7.5 m) to get the lock feature
to disengage.
Shifting into Four-Wheel-Low Lock
To shift into Four-Wheel-Low Lock, the ignition must be in
RUN and the vehicle must be stopped or moving less
than 3 mph (5 km/h) with the transmission in
NEUTRAL (N). The preferred method for shifting into
Four-Wheel Low is to have your vehicle moving
1 to 2 mph (1.6 to 3.2 km/h). Press and release the
Four-Wheel-Low Lock button. You must wait for the
Four-Wheel-Low Lock indicator light to stop flashing and
remain lit before shifting your transmission in gear.
Notice: Shifting the transmission into gear before
the indicator light stops flashing could cause
damage to the transfer case. Always wait until the
indicator light stops flashing before putting the
transmission back in gear.
It is normal for your vehicle to have engagement noise
and bump when shifting between Four-Wheel Low
and Four-Wheel High or Four-Wheel-High Lock ranges
or from NEUTRAL with the engine running.
If the Four-Wheel-Low Lock button is pressed when
your vehicle is in gear and/or moving, the Four-Wheel
Low Lock indicator light will flash for 15 seconds and not
complete the shift unless your vehicle is moving less
than 3 mph (5 km/h) and the transmission is in
NEUTRAL (N). After 15 seconds the transfer case will
return to the setting last chosen.
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