GMC Yukon Denalid Owner's Manual page 131

When driving with the liftgate open, the power
liftgate should be switched to manual liftgate
operation — the overhead console switch set to
the "Disable" position.
Both the liftglass and liftgate have an electric
latch. If the battery is disconnected or has
low voltage, the liftglass and liftgate will not open.
The liftglass and liftgate will resume operation
when the battery is reconnected and charged.
If the battery is properly connected and has
adequate voltage, and the liftgate or liftglass still
will not function, your vehicle should be taken to a
dealership for service.
CAUTION:
{
It can be dangerous to drive with the
liftglass or liftgate open because carbon
monoxide (CO) gas can come into your
vehicle. You cannot see or smell CO. It
can cause unconsciousness and even
death.
CAUTION: (Continued)
CAUTION: (Continued)
If you must drive with the liftglass or
liftgate open, or if electrical wiring or
other cable connections must pass
through the seal between the body and
the liftglass or liftgate:
•
Make sure all other windows are shut.
•
Turn the fan on your heating or
cooling system to its highest speed
with the recirculation mode off. That
will force outside air into your vehicle.
See Dual Automatic Climate Control
System on page 214.
•
If you have air outlets on or under
the instrument panel, open them all
the way.
•
If your vehicle is equipped with a
power liftgate, disable the power
liftgate function.
See Engine Exhaust on page 156.
Do not drive with the liftgate open if at all possible.
131