GMC 2007 Yukon XL Owner's Manual page 206

The display has three color-coded lights.
The URPA lights are used to provide distance
and system information, along with beeps that will
be heard through the speakers.
206
The display is located
near the passenger side
rear window and can
be seen by looking over
your right shoulder.
URPA can be turned off
by pressing the rear
park aid disable button
located next to the
radio. The indicator will
illuminate to indicate
that URPA is off.
The red light in the URPA display will also be lit if
the vehicle is in REVERSE (R). If the vehicle
has a DIC, PARKING ASSIST OFF will display.
URPA automatically turns back on each time
the vehicle is started.
How the System Works
When the shift lever is moved into REVERSE (R),
the rear display will briefly come on to let you know
the display is operating correctly. URPA comes on
automatically when the shift lever is moved into
REVERSE (R). The system also does not work at a
reverse speed greater than 5 mph (8 km/h).
To remind you of this, the red light on the rear
display will flash.
The system can be disabled using the Driver
Information Center (DIC). See DIC Operation and
Displays (With DIC Buttons) on page 244 or
DIC Operation and Displays (Without DIC Buttons)
on page 251.