GM Service Manual Online
For 1990-2009 cars only

Each power mirror has 2 reversible motors. One motor adjusts the mirror view left and right. The other motor adjusts the mirror up and down. First the driver must select which mirror is to be moved by placing the mirror select switch in either the LEFT MIRROR position or the RIGHT MIRROR position. The driver then operates the mirror switch in one of the following positions in order to control the polarity of the battery voltage applied to the mirrors:

    • UP
    • DOWN
    • LEFT
    • RIGHT

The battery voltage is applied from the engine compartment fuse relay MIRROR fuse to either the left or right power mirror. As the mirror is operated, the battery voltage is supplied through the contacts of that direction to the motor. The motor is grounded through the contacts of the opposite direction.

The memory mirrors are controlled by the memory mirror module (MMM). The MMM controls the movement of the 4 mirror motors: 2 motors for the left mirror and 2 motors for the right mirror. All of the motors operate independently of each other. Each motor has an attached position sensor.

The engine compartment fuse/relay center MIRROR fuse supplies the battery positive voltage (B+) via CKT 1740 (ORN) in order to power the MMM and the mirror motors. Ground for the MMM is provided via CKT 50 (BLK) to G204.

Motors

Each mirror has 2 motors. Each mirror has the following components:

    • An up/down motor
    • A left/right motor

All of the motors are reversible. The mirror is moved up and down by one motor. When the MMM receives an input in order to move the mirror up, the MMM supplies battery positive voltage (B+) and ground to run the motor in order to move the mirror up. When the MMM receives a mirror down input, the MMM supplies power to the same motor, although the voltage and ground are on the opposite motor cavities. The voltage polarity is reversed and the motor runs the opposite direction. This condition moves the mirror down.

Position Sensors

The position sensors are used by the MMM in order to perform the following functions:

    • Store the motor positions in the memory
    • Return the motors to the stored memory positions

The MMM provides a 5 V reference voltage through CKT 674 (YEL). The MMM provides reference ground through CKT 675 (LT GRN) to each mirror position sensor. These sensors are potentiometers that are mounted to each motor's transmission cable. When the cable rotates, the resistance of the potentiometer varies. The feedback voltage is monitored by the MMM in order to determine the motor position. The sensor feedback voltages vary from 0.25-4.75 V. When a set memory command is executed, the MMM stores the motor positions by recording each position sensor feedback voltage. When a memory recall is commanded, the module moves the motors until all of the position sensor feedback voltages equal the feedback voltages stored in the memory. For the easy exit functions, only the seat position sensor feedback voltages are recorded and only the seat motors run.

Manual Movement

The MMM receives the inputs from the power mirror switch in order to move the mirrors. Only one mirror may be moved at a time. The mirror select switch must be placed in either the LEFT MIRROR position or the RIGHT MIRROR position before a mirror may be moved. Moving the mirror switch sends inputs to the MMM. When the MMM sees a valid input, the MMM supplies battery positive voltage (B+) to the appropriate mirror motor(s).

Memory Set

The MMM receives the inputs from the memory functions switch. The following positions may be recorded for 2 different drivers:

    • Current seat
    • Seatback
    • Lumbar
    • Mirror

In order to record the current positions, press the SET MEMORY button. A chime acknowledges the input. Within 5 seconds, press one of the following buttons:

    •  MEMORY-1
    • MEMORY-2

When the MMM receives these inputs, the MMM records the feedback voltages from the 4 mirror position sensors for the appropriate driver. A single chime acknowledges that the position was recorded. The MMM sends a Class 2 message to the memory seat module (MSM). This action informs the module of the SET MEMORY command. The MSM then records the feedback voltages for all of the seat and lumbar position sensors for the appropriate driver. An easy exit position for each driver may also be recorded. In order to perform this function, refer to Memory Seats.

Memory Recall

When the MEMORY-1 or MEMORY-2 button is pressed, the following actions occur:

  1. The MMM receives the input.
  2. A single chime sounds.

The MMM applies the battery positive voltage (B+) to the mirror motors until all of the mirror position sensor feedback voltages equal the feedback voltages stored in the memory for the appropriate driver. The MMM also commands the MSM to perform the memory recall function via a Class 2 message. The MSM then applies the battery positive voltage (B+) to all of the seat and lumbar support motors until the position sensor feedback voltages equal the feedback voltages stored in the memory for the appropriate driver.

Recall Personalization

When a keyless entry transmitter is used in order to unlock the vehicle doors, the remote function actuator (RFA) communicates the unlock command via a Class 2 message. Three personalized recall options exist when the MMM receives an unlock message:

    • Recall immediately upon receipt of the RFA message.
    • Recall when a key-in message is received.
    • Do not recall upon receipt of an RFA message. Recall functions are only performed with the memory switches.

Memory Inhibit/Enable

The MMM receives the park gear and ignition inputs via Class 2 messages. When the ignition switch is in the OFF position, the following recall functions are allowed:

    • Memory record
    • Memory recall
    • Personalization recall
    • Exit recall

The personalization recall function is deactivated and all of the other memory functions are allowed when the following conditions are present:

    • The ignition switch is in the ON position.
    • The gear selector is in the PARK position.

The memory recall function is allowed only on a press and hold basis when the following conditions are present:

    • The ignition switch is in the ON position.
    • The gear selector is out of the PARK position.

When the MEMORY-1 or MEMORY-2 button is pressed and held, the MMM performs the following functions:

    • Moves the mirrors
    • Commands the MSM to move the seat

The MMM performs these functions until one of the following actions occur:

    • The seat and mirrors reach their destination.
    • The recall button is released.
    • Any mirror or seat positioning switch is activated.

Curb View Assist Mirror (If Equipped with Memory)

If the vehicle has this personalization feature, MIRROR TILT IN REV will be the fourth personalization prompt to display on the DIC.

In order to program the vehicle, press the SKIP INTO and NO INFO RESET buttons at the same time for about 2 seconds. When MIRROR TILT IN REV appears, a yes or no response is needed. Press the YES TRIP RESET button in order to answer yes or the NO INFO RESET button in order to answer no.

FEATURE ON displays when a yes response is made and FEATURE OFF shows after a no response.