My Traverse has been at the dealer 4 times for the same problem. The passenger mirror will not return to the correct position after tilting down to reverse. It turns down and in. This problem is also triggered by switching from one seat memory to the other. It doesn't happen every time. The dealer can not replicated the problem. The dealer did replace the mirror but it continues to happen. Sometime the mirror motor runs constantly trying to turn down and in until I use the door controls to adjust the mirror.

The passenger mirror system is designed to point down when reversing- if the mirror adjust switch is to the driver side. If you don't wish to have it do this, keep the adjust selector switch pointed to the passenger side. If that switch is malfunctioning it could also explain why you cannot adjust the driver's mirror.

Mirror Tilt in Reverse Controls
This feature is capable of tilting the passenger side power mirror when the transmission is placed in reverse to provide enhanced visibility during parking or backing maneuvers. This feature is turned OFF or ON through the DIC. The passenger mirror on domestic vehicles can not be changed from the factory setting, but on export vehicles, the passenger mirror position may by changed using the same procedure as the driver mirror. For further information, refer to Driver Personalization in Personalization.

Tilt Mirror In Reverse
Continue with the following steps in order to personalize the tilt mirror in reverse.
Press the Select button in order to enter the menu. The first choice seen is the current setting.
Press the Select button in order to scroll through the following options:
• CURB VIEW: OFF (Default)
• CURB VIEW: PASSENGER
Press the Personalization button in order to advance to the next option.

this might be what you're experiencing.......
Park Tilt Mirrors
If the vehicle has the memory
package, the outside mirrors
have a park tilt feature. This feature
automatically tilts the outside
mirrors to a preselected position
when the vehicle is in R (Reverse).
This allows the driver to view the
curb for parallel parking.
The passenger and driver mirrors
return to their original position
when the vehicle is shifted out of
R (Reverse), or the ignition is turned
off or to OFF/LOCK.
This feature can be turned on or
off through the Driver Information
Center (DIC)

The audio system controls are used
to access the personalization
menus for customizing vehicle
features. (DIC)
CONFIG (Configuration):
Press
to access the Configuration
Settings Menu.
MENU / SELECT Knob:
Press the
center of this knob to enter the
menus and select menu items.
Turn the knob to scroll through the
menus.
0
BACK:
Press to exit or move
backwards in a menu.

Sure hope this helps!
Best to you.

I don't know for sure , but I would think that only the curb side one would.

The power mirrors are controlled by a module (computer) DDM - drivers door module an the PDM - passenger door module .
Folding Mirror System
Folding Mirror System Controls
The folding mirror system requires signals from 2 separate switches. The mirror select switch must be in the neutral/fold position and the mirror direction switch must be activated to the left/extend or right/retract positions. Both switches are integrated into the DDM and provide direct signals.
Folding Mirror System Operation
Upon receipt of the required switch inputs the DDM will supply battery voltage and ground to the mirror fold motor control circuits to perform the requested extend or retract function. The DDM will also send a class 2 message to the PDM indicating the requested function. The PDM will supply battery voltage and ground to the mirror fold motor control circuits to perform the requested extend or retract function.

Power Mirror System
Power Mirror System Components
The power mirror system consists of the following components:
• The driver door module--Class 2 module with integrated switches and requires programming when replaced
• The passenger door module--Class 2 module with integrated switches, requires programming when replaced and also contains the RFA receiver
• The power mirror direction switch--Integrated into DDM and is a 4-position momentary switch that provides a signal input to the DDM for up, down, left/extend and right/retract with a mirror switch activation
• The mirror select switch--Integrated into DDM and is a 3-position switch that allows the operator to select the left or right mirror and also a neutral/fold position
• The left outside power mirror--Contains both the vertical and horizontal mirror motors and is serviced as a complete mirror assembly
• The right outside power mirror--Contains both the vertical and horizontal mirror motors and is serviced as a complete mirror assembly
• The body control module--Class 2 module that requires programming when replaced, serves as the power mode master and is the main message handler
• The DDM 10A fuse--Located in the I/P fuse block and is hot at all times
• The PDM 10A fuse--Located in the I/P fuse block and is hot at all times
• The memory switch, if equipped with memory mirrors--Supplied power by the DDM and provides a voltage signal to the DDM upon a switch activation
• The horizontal and vertical position sensors, if equipped with memory mirrors--Supplied a 5-volt and low reference by the DDM/PDM and provide a variable voltage signal to the DDM/PDM that is proportional to mirror position
• The park neutral position switch, if equipped with memory mirrors--Provides transmission gear selection information to the PCM and is used for memory recall and mirror tilt in reverse functions
• The powertrain control module, if equipped with memory mirrors--Class 2 module that requires programming when replaced and provides Class 2 message indicating transmission gear selection
• The driver information center (DIC), if equipped with memory mirrors--Part of the instrument cluster which is a Class 2 module that requires programming when replaced and is used to personalize the memory recall and mirror tilt in reverse functions
• Fold motor in each of the outside mirrors, if equipped with power fold mirrors--Provides extend and retract movements of the mirror and is serviced as a complete mirror assembly
Each of the outside power mirrors contains 2 reversible motors to provide horizontal and vertical movement of the mirror glass. The vertical motor operates the up and down directions and the horizontal motor operates the left and right directions. If equipped with power folding mirrors, each outside power mirror will contain a reversible fold motor to operate the extend and retract functions. Each of the mirror motors are circuit breaker protected.
DTC B1722
The driver door module (DDM) and passenger door module (PDM) switch the mirror fold motor control circuits to battery voltage and ground in response to mirror extend or retract command.

There are two power wires to the DDM - drivers door module .Both are orange ,one is powered by a fuse DDM fuse 15amp . in the left I/P fuse block , plus LT DOORS 25amp circuit breaker .
Power Mirror System Components
The power mirror system consists of the following components:
• The driver door module--Class 2 module with integrated switches and requires programming when replaced
• The passenger door module--Class 2 module with integrated switches, requires programming when replaced and also contains the RFA receiver
• The power mirror direction switch--Integrated into DDM and is a 4-position momentary switch that provides a signal input to the DDM for up, down, left/extend and right/retract with a mirror switch activation
• The mirror select switch--Integrated into DDM and is a 3-position switch that allows the operator to select the left or right mirror and also a neutral/fold position
• The left outside power mirror--Contains both the vertical and horizontal mirror motors and is serviced as a complete mirror assembly
• The right outside power mirror--Contains both the vertical and horizontal mirror motors and is serviced as a complete mirror assembly
• The body control module--Class 2 module that requires programming when replaced, serves as the power mode master and is the main message handler
• The DDM 10A fuse--Located in the I/P fuse block and is hot at all times
• The PDM 10A fuse--Located in the I/P fuse block and is hot at all times
• The memory switch, if equipped with memory mirrors--Supplied power by the DDM and provides a voltage signal to the DDM upon a switch activation
• The horizontal and vertical position sensors, if equipped with memory mirrors--Supplied a 5-volt and low reference by the DDM/PDM and provide a variable voltage signal to the DDM/PDM that is proportional to mirror position
• The park neutral position switch, if equipped with memory mirrors--Provides transmission gear selection information to the PCM and is used for memory recall and mirror tilt in reverse functions
• The powertrain control module, if equipped with memory mirrors--Class 2 module that requires programming when replaced and provides Class 2 message indicating transmission gear selection
• The driver information center (DIC), if equipped with memory mirrors--Part of the instrument cluster which is a Class 2 module that requires programming when replaced and is used to personalize the memory recall and mirror tilt in reverse functions
• Fold motor in each of the outside mirrors, if equipped with power fold mirrors--Provides extend and retract movements of the mirror and is serviced as a complete mirror assembly
Each of the outside power mirrors contains 2 reversible motors to provide horizontal and vertical movement of the mirror glass. The vertical motor operates the up and down directions and the horizontal motor operates the left and right directions. If equipped with power folding mirrors, each outside power mirror will contain a reversible fold motor to operate the extend and retract functions. Each of the mirror motors are circuit breaker protected.

Do you know what DTC'S are ? Diagnostic trouble codes
DTC B1544, B1600, or B1605
DTC B1580, B1590, B1610, or B1620
• If DTC B1580 is set by itself, the left horizontal position sensor signal circuit maybe open, shorted to ground or battery
• If DTC B1590 is set by itself, the left vertical position sensor signal circuit maybe open, shorted to ground or battery
• If DTC B1610 is set by itself, the right horizontal position sensor signal circuit maybe open, shorted to ground or battery
• If DTC B1620 is set by itself, the right vertical position sensor signal circuit maybe open, shorted to ground or battery.
• If DTCs B1580 and B1590 are both set, the left 5 volt reference or low reference circuit(s) maybe open, shorted to ground or battery.
• If DTCs B1610 and B1620 are both set, the right 5 volt reference or low reference circuit(s) maybe open, shorted to ground or battery.
Need a factory scan tool to test !
Install a scan tool.
Turn ON the ignition, with the engine OFF.
With the scan tool, observe the mirror horizontal and vertical position parameters in the Driver Door Module (DDM) and Passenger Door Module (PDM) data lists.
Operate both the left and right mirrors through the full range of movements.
Does the scan tool indicate that the left and right mirror horizontal and vertical position parameters are within the specified range?
0.50-4.75 V.
Your best bet , take it to a GMC , Chevy , buick or cadillac dealer

sounds like it ,these fancy new cars and their electronics,a mechanics nightmare to be truthfull.try reading the manual again if still no success then take it back to dealer as you could have a fault in the controlling processor.

here's 2003, don't have 2008

Removal
NOTE: Left-hand dual arm mirror with heat shown, non-heated and aero mirrors similar.
All exterior mirrors

1. Position the exterior mirror glass in the full down position.

1. Grasp the top and carefully pull the exterior mirror glass away from the mirror housing.

1. Disconnect the electrical terminals (if equipped) and remove the exterior mirror glass.

Power exterior mirrors

1. Remove the jack pins from the exterior mirror glass backing plate.
   • Use pliers to grasp the jack pins at the base to remove.

Installation
Power exterior mirrors

1. Remove the sealing boots from the exterior mirror motor.

1. Install the jack pins in the sealing boots.

1. Install the jack pins and sealing boots.
   1. Hold the legs of the jack pins and push the jack pins back into the exterior mirror housing.
   1. Install the sealing boots so the boot shoulder is under the mirror collar and turn each jack pin until the head of the jack pin is aligned with the slots in the sockets on the backing glass plate.

All exterior mirrors

1. Place the new exterior mirror glass assembly down on a smooth firm surface.

1. Align the friction pins vertically to the exterior mirror glass backing plate socket and push down to snap the pivot ball into the socket.

1. CAUTION: Do not over heat the exterior mirror glass backing plate. Heat only until backing plate is warm to the touch.
   Using the special tool, warm the main pivot sockets in exterior mirror glass backing plate.

1. Loosely install the glass.
   1. Connect the electrical wiring to the electrical terminals (if equipped).
   1. Position the friction pins in the mirror housing.
   1. Align the jack pin locating tabs to match with the mirror glass back.

1. Using a flat hand, press on the center of the mirror glass until seated on the center pivot of the mirror housing.
   • Press the mirror glass toward one of the jack pins until snapped in place.
   • Repeat for second jack pin.

Power exterior mirrors
NOTE: If the jack pins do not engage, they may not be aligned correctly. Remove the exterior mirror glass, align the jack pins to the slots in the sockets and repeat the installation procedure.

1. NOTE: The jack pin should click while manually adjusting the exterior mirror glass.
   Tilt the exterior mirror glass to the full outboard position and then press on the outer side of the class until the in/out jack pin snaps into the socket on the exterior mirror backing plate.

1. NOTE: The jack pin should click while manually adjusting the exterior mirror glass.
   Tilt the exterior mirror glass to the full down position and then press on the outer side of the class until the up/down jack pin snaps into the socket on the exterior mirror backing plate.