Buick Regal: Power Mirror Malfunction (with A45)
Diagnostic Instructions
- Perform the Diagnostic System Check - Vehicle prior to using this
diagnostic procedure.
- Review Strategy Based Diagnosis for an overview of the diagnostic
approach.
- Diagnostic Procedure Instructions provides an overview of each
diagnostic category.
Diagnostic Fault Information
1. Outside Rearview Mirror Switch Malfunction
2. Driver or Passenger Outside Power Mirror Malfunction
3. Power Mirror Memory Feature Malfunction
Circuit/System Description
The outside mirror switch and passenger window switch are on a serial data
circuit with the memory
seat module as the master. The mirror select and directional control switches
are inputs to the memory
seat module through the serial data circuit. When the memory seat module
receives switch inputs from
the outside mirror switch, mirror output commands are sent to the appropriate
switch through the serial
data circuit. The outside mirror switch and passenger window switch control the
left and right outside
rear view mirrors through bi-directional motor control circuits. The motor
control circuits are floating
while in an inactive state and the switches will apply power and ground to the
control circuits as
necessary to move the mirror in the commanded direction.
Mirror position is determined by both horizontal and vertical position sensors
in each of the power
mirrors. The outside mirror switch and passenger window switch supply a 5 V
reference, low reference,
and horizontal and vertical position signal circuits to these sensors. The
signal circuits are referenced
from 5 V by the switches and the signal circuit voltage levels represent the
mirror positions. The mirror
positions are sent to the memory seat module through the serial data circuit
where they are stored for
memory mirror operation. When the memory seat module receives a memory recall
command, the
memory seat module will send the go to position commands to the outside mirror
switch and passenger
window switch. The switches will then drive the appropriate mirror motors to the
commanded position
sensor settings.
Reference Information
Schematic Reference
Outside Rearview Mirror Wiring Schematics
Connector End View Reference
COMPONENT CONNECTOR END VIEWS - INDEX
Description and Operation
Outside Mirror Description and Operation (With A45)
Electrical Information Reference
- Circuit Testing
- Connector Repairs
- Testing for Intermittent Conditions and Poor Connections
- Wiring Repairs
Scan Tool Reference
Control Module References for scan tool information.
Circuit/System Verification
1. Ignition ON.
2. Verify the scan tool Mirror Select Switch parameter changes from None to Left
and Right when
cycling the S146 Outside Rearview Mirror Switch.
- If the parameter does not change
Refer to Circuit/System Testing - Outside Rearview Mirror Switch
Malfunction.
- Go to next step: If the parameter changes
3. Verify the scan tool Mirror Direction Switch parameter changes from
Inactive to Up, Down, Right
and Left when cycling the S146 Outside Rearview Mirror Switch.
- If the parameter does not change
Refer to Circuit/System Testing - Outside Rearview Mirror Switch
Malfunction.
- Go to next step: If the parameter changes
4. Verify the A9A Outside Rearview Mirror - Driver moves when commanding the
Driver Mirror
Horizontal Movement Right/Left and Driver Mirror Vertical Movement Up/Down with
a scan
tool.
- If the A9A Outside Rearview Mirror - Driver does not move RIGHT or
LEFT or UP
or DOWN
Refer to Circuit/System Testing - Driver Outside Mirror Movement
Malfunction.
- Go to next step: If the A9A Outside Rearview Mirror - Driver moves
RIGHT, LEFT,
UP and DOWN
5. Verify the scan tool Driver Mirror Vertical Position parameters are
between 0.2 - 4.8 V and change
when commanding the Driver Mirror Vertical Movement Up/Down with a scan tool.
- If not between 0.2 - 4.8 V or does not change
Refer to Circuit/System Testing - Driver Mirror Position Sensor Circuit
Test.
- Go to next step: If between 0.2 - 4.8 V and changes
6. Verify the scan tool Driver Mirror Horizontal Position parameters are
between 0.2 - 4.8 V and
change when commanding the Driver Mirror Horizontal Movement Right/Left with a
scan tool.
- If not between 0.2 - 4.8 V or does not change
Refer to Circuit/System Testing - Driver Mirror Position Sensor Circuit
Test.
- Go to next step: If between 0.2 - 4.8 V and changes
7. Verify the A9B Outside Rearview Mirror-Passenger moves when commanding the
Passenger
Mirror Horizontal Movement Right/Left and Passenger Mirror Vertical Movement
Up/Down with
a scan tool.
- If the A9B Outside Rearview Mirror-Passenger does not move RIGHT or
LEFT or UP
or DOWN
Refer to Circuit/System Testing - Passenger Outside Mirror Movement
Malfunction.
- Go to next step: If the A9B Outside Rearview Mirror-Passenger moves
RIGHT, LEFT,
UP and DOWN
8. Verify the scan tool Passenger Mirror Vertical Position parameters are
between 0.2 - 4.8 V and
change while commanding the Passenger Mirror Horizontal Movement Right/Left with
a scan
tool.
- If not between 0.2 - 4.8 V or does not change
Refer to Circuit/System Testing - Passenger Mirror Position Sensor
Circuit Test.
- Go to next step: If between 0.2 - 4.8 V and changes
9. Verify the scan tool Passenger Mirror Horizontal Position parameters are
between 0.2 - 4.8 V and
change while commanding the Passenger Mirror Vertical Movement Up/Down with a
scan tool.
- If not between 0.2 - 4.8 V or does not change
Refer to Circuit/System Testing - Passenger Mirror Position Sensor
Circuit Test.
- Go to next step: If between 0.2 - 4.8 V and changes
10. All OK.
Circuit/System Testing
Outside Rearview Mirror Switch Malfunction
1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector
at the S146 Outside
Rearview Mirror Switch. It may take up to 2 minutes for all vehicle systems to
power down.
2. Test for less than 10 Ω between the ground circuit terminal 24 and ground.
- Ignition OFF.
- Test for less than 2 Ω in the ground circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, repair the open/high resistance in the ground
connection.
- Go to next step: If less than 10 Ω
3. Verify a test lamp illuminates between the B+ circuit terminal 23 and
ground.
- If the test lamp does not illuminate and the circuit fuse is good
- Ignition OFF, remove the test lamp.
- Test for less than 2 Ω in the ignition circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, verify the fuse is not open and there is voltage
at the fuse.
- If the test lamp does not illuminate and the circuit fuse is open
- Ignition OFF, remove the test lamp.
- Test for infinite resistance between the B+ circuit and ground.
- If less than infinite resistance, repair the short to ground on the
circuit.
- Go to next step: If infinite resistance
- Test for infinite resistance between the signal circuit and ground.
- If less than infinite resistance, repair the short to ground on the
circuit.
- If infinite resistance, replace the S146 Outside Rearview Mirror
Switch
- Go to next step: If the test lamp illuminates
4. Test or replace the S146 Outside Rearview Mirror Switch.
Driver Outside Mirror Movement Malfunction
1. Ignition OFF, disconnect the harness connector at the A9A Outside Rearview
Mirror-Driver.
Ignition ON.
2. Connect a test lamp between the control circuit terminal 9 and control
circuit terminal 12.
3. Verify the test lamp turns ON when commanding the Up and Down states with a
scan tool.
- If the test lamp remains OFF during either of the commands
- Ignition OFF, remove the test lamp, disconnect the harness connector at
the S146 Outside
Rearview Mirror Switch.
- Test for infinite resistance between each control circuit and ground.
- If less than infinite resistance, repair the short to ground on the
circuit.
- Go to next step: If infinite resistance
- Test for less than 2 Ω in each control circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the S146 Outside Rearview Mirror Switch.
- If the test lamp is always ON
- Ignition OFF, remove the test lamp, disconnect the harness connector at
the S146 Outside
Rearview Mirror Switch, ignition ON.
- Test for less than 1 V between each control circuit and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V, replace the S146 Outside Rearview Mirror Switch
- Go to next step: If the test lamp turns ON during each of the
commands
4. Connect a test lamp between the control circuit terminal 10 and control
circuit terminal 12.
5. Verify the test lamp turns ON when commanding the Left and Right states
with a scan tool.
- If the test lamp remains OFF during either of the commands
- Ignition OFF, remove the test lamp, disconnect the harness connector at
the S146 Outside
Rearview Mirror Switch.
- Test for infinite resistance between each control circuit and ground.
- If less than infinite resistance, repair the short to ground on the
circuit.
- Go to next step: If infinite resistance
- Test for less than 2 Ω in each control circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the S146 Outside Rearview Mirror Switch.
- If the test lamp is always ON
- Ignition OFF, remove the test lamp, disconnect the harness connector at
the S146 Outside
Rearview Mirror Switch, ignition ON.
- Test for less than 1 V between each control circuit and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V, replace the S146 Outside Rearview Mirror Switch
- Go to next step: If the test lamp turns ON during each of the
commands
6. Test or replace the M77D Outside Rearview Mirror Motor-Driver.
Driver Mirror Position Sensor Circuit Test
1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector
at the A9A Outside
Rearview Mirror-Driver. It may take up to 2 minutes for all vehicle systems to
power down.
2. Test for less than 10 Ω between the low reference circuit terminal 3 and
ground.
- Ignition OFF, disconnect the harness connector at the S146 Outside
Rearview Mirror
Switch.
- Test for less than 2 Ω in the low reference circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the S146 Outside Rearview Mirror Switch.
- Go to next step: If less than 10 Ω
3. Ignition ON.
4. Test for 4.8 - 5.2 V between the 5 V reference circuit terminal 17 and
ground.
- Ignition OFF, disconnect the harness connector at the S146 Outside
Rearview Mirror
Switch.
- Test for infinite resistance between the 5 V reference circuit and
ground.
- If less than infinite resistance, repair the short to ground on the
circuit.
- Go to next step: If infinite resistance
- Test for less than 2 Ω in the 5 V reference circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the S146 Outside Rearview Mirror Switch.
- Ignition OFF, disconnect the harness connector at the S146 Outside
Rearview Mirror
Switch, ignition ON.
- Test for less than 1 V between the 5 V reference circuit and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V, replace the S146 Outside Rearview Mirror Switch.
- Go to next step: If between 4.8 - 5.2 V
5. Verify the scan tool Driver Mirror Vertical Position parameter is less
than 4.6 V.
- Ignition OFF, disconnect the harness connector at the S146 Outside
Rearview Mirror
Switch, ignition ON.
- Test for less than 1 V between the signal circuit terminal 14 and
ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V, replace the S146 Outside Rearview Mirror Switch.
- Go to next step: If less than 4.6 V
6. Install a 3 A fused jumper wire between the signal circuit terminal 14 and
the 5 V reference circuit
terminal 17.
7. Verify the scan tool Driver Mirror Vertical Position or the parameter is
greater than 0.6 V.
- Ignition OFF, remove the jumper wire, disconnect the harness connector
at the S146
Outside Rearview Mirror Switch.
- Test for infinite resistance between the signal circuit terminal 1 and
ground.
- If less than infinite resistance, repair the short to ground on the
circuit.
- Go to next step: If infinite resistance
- Test for less than 2 Ω in the signal circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the S146 Outside Rearview Mirror Switch.
- Go to next step: If greater than 0.6 V
8. Verify the scan tool Driver Mirror Horizontal Position parameter is less
than 4.6 V.
- Ignition OFF, disconnect the harness connector at the S146 Outside
Rearview Mirror
Switch, ignition ON.
- Test for less than 1 V between the signal circuit terminal 7 and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V, replace the S146 Outside Rearview Mirror Switch.
- Go to next step: If less than 4.6 V
9. Install a 3 A fused jumper wire between the signal circuit terminal 7 and
the 5 V reference circuit
terminal 17.
10. Verify the scan tool Driver Mirror Horizontal Position or the parameter is
greater than 0.6 V.
- Ignition OFF, remove the jumper wire, disconnect the harness connector
at the S146
Outside Rearview Mirror Switch.
- Test for infinite resistance between the signal circuit terminal 1 and
ground.
- If less than infinite resistance, repair the short to ground on the
circuit.
- Go to next step: If infinite resistance
- Test for less than 2 Ω in the signal circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the S146 Outside Rearview Mirror Switch.
- Go to next step: If greater than 0.6 V
11. Test or replace the M77D Outside Rearview Mirror Motor-Driver.
Passenger Outside Mirror Movement Malfunction
1. Ignition OFF, disconnect the harness connector at the A9B Outside Rearview
Mirror-Passenger.
Ignition ON.
2. Connect a test lamp between the control circuit terminal 9 and control
circuit terminal 12.
3. Verify the test lamp turns ON when commanding the Up and Down states with a
scan tool.
- If the test lamp remains OFF during either of the commands
- Ignition OFF, remove the test lamp, disconnect the X2 harness connector
at the S79P
Window Switch-Passenger.
- Test for infinite resistance between each control circuit and ground.
- If less than infinite resistance, repair the short to ground on the
circuit.
- Go to next step: If infinite resistance
- Test for less than 2 Ω in each control circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the S79P Window Switch-Passenger.
- If the test lamp is always ON
- Ignition OFF, remove the test lamp, disconnect the X2 harness connector
at the S79P
Window Switch-Passenger, ignition ON.
- Test for less than 1 V between each control circuit and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V, replace the S79P Window Switch-Passenger
- Go to next step: If the test lamp turns ON during each of the
commands
4. Connect a test lamp between the control circuit terminal 10 and control
circuit terminal 12.
5. Verify the test lamp turns ON when commanding the Left and Right states with
a scan tool.
- If the test lamp remains OFF during either of the commands
- Ignition OFF, remove the test lamp, disconnect the X2 harness connector
at the S79P
Window Switch-Passenger.
- Test for infinite resistance between each control circuit and ground.
- If less than infinite resistance, repair the short to ground on the
circuit.
- Go to next step: If infinite resistance
- Test for less than 2 Ω in each control circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the S79P Window Switch-Passenger.
- If the test lamp is always ON
- Ignition OFF, remove the test lamp, disconnect the X2 harness connector
at the S79P
Window Switch-Passenger, ignition ON.
- Test for less than 1 V between each control circuit and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V, replace the S79P Window Switch-Passenger
- Go to next step: If the test lamp turns ON during each of the
commands
6. Test or replace the M77P Outside Rearview Mirror Motor-Passenger.
Passenger Mirror Position Sensor Circuit Test
1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector
at the A9B Outside
Rearview Mirror-Passenger. It may take up to 2 minutes for all vehicle systems
to power down.
2. Test for less than 10 Ω between the low reference circuit terminal 3 and
ground.
- Ignition OFF, disconnect the X2 harness connector at the S79P Window
Switch-Passenger.
- Test for less than 2 Ω in the low reference circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the S79P Window Switch-Passenger.
- Go to next step: If less than 10 Ω
3. Ignition ON.
4. Test for 4.8 - 5.2 V between the 5 V reference circuit terminal 17 and
ground.
- Ignition OFF, disconnect the X2 harness connector at the S79P Window
Switch-Passenger.
- Test for infinite resistance between the 5 V reference circuit and
ground.
- If less than infinite resistance, repair the short to ground on the
circuit.
- Go to next step: If infinite resistance
- Test for less than 2 Ω in the 5 V reference circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the S79P Window Switch-Passenger.
- Ignition OFF, disconnect the X2 harness connector at the S79P Window
Switch-Passenger,
ignition ON.
- Test for less than 1 V between the 5 V reference circuit and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V, replace the S79P Window Switch-Passenger.
- Go to next step: If between 4.8 - 5.2 V
5. Verify the scan tool Passenger Mirror Vertical Position parameter is less
than 4.6 V.
- Ignition OFF, disconnect the X2 harness connector at the S79P Window
Switch-Passenger,
ignition ON.
- Test for less than 1 V between the signal circuit terminal 9 and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V, replace the S79P Window Switch-Passenger.
- Go to next step: If less than 4.6 V
6. Install a 3 A fused jumper wire between the signal circuit terminal 9 and
the 5 V reference circuit
terminal 17.
7. Verify the scan tool Passenger Mirror Vertical Position or the parameter is
greater than 0.6 V.
- Ignition OFF, remove the jumper wire, disconnect the X2 harness
connector at the S79P
Window Switch-Passenger.
- Test for infinite resistance between the signal circuit terminal 9 and
ground.
- If less than infinite resistance, repair the short to ground on the
circuit.
- Go to next step: If infinite resistance
- Test for less than 2 Ω in the signal circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the S79P Window Switch-Passenger.
- Go to next step: If greater than 0.6 V
8. Verify the scan tool Passenger Mirror Horizontal Position parameter is
less than 4.6 V.
- Ignition OFF, disconnect the X2 harness connector at the S79P Window
Switch-Passenger,
ignition ON.
- Test for less than 1 V between the signal circuit terminal 7 and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V, replace the S79P Window Switch-Passenger.
- Go to next step: If less than 4.6 V
9. Install a 3 A fused jumper wire between the signal circuit terminal 7 and
the 5 V reference circuit
terminal 17.
10. Verify the scan tool Passenger Mirror Horizontal Position or the parameter
is greater than 0.6 V.
- Ignition OFF, remove the jumper wire, disconnect the X2 harness
connector at the S79P
Window Switch-Passenger.
- Test for infinite resistance between the signal circuit terminal 7 and
ground.
- If less than infinite resistance, repair the short to ground on the
circuit.
- Go to next step: If infinite resistance
- Test for less than 2 Ω in the signal circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the S79P Window Switch-Passenger.
- Go to next step: If greater than 0.6 V
11. Test or replace the M77P Outside Rearview Mirror Motor-Passenger.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
- Outside Rearview Mirror Actuator Replacement
- Front Side Door Window Switch Replacement
- Front Side Door Window Switch Replacement
READ NEXT:
Diagnostic Instructions
Perform the Diagnostic System Check - Vehicle prior to using this
diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic
approach
Diagn
Diagnostic Instructions
Perform the Diagnostic System Check - Vehicle prior to using this
diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic
approach.
Diag
Outside Rearview Mirror Replacement
Preliminary Procedures
Front Side Door Window Garnish Molding Replacement.
Outside Rearview Mirror Bolt [3x]
CAUTION:
Fastener Caution.
Tighten
9 N.m (80 lb
SEE MORE:
Diagnostic Instructions
Perform the Diagnostic System Check - Vehicle prior to using this
diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic
approach.
Refer to Diagnostic Procedure Instructions provide an overview of each
diagnostic category.
DTC Descr
Diagnostic Instructions
Perform the Diagnostic System Check - Vehicle prior to using this
diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic
approach.
Diagnostic Procedure Instructions provides an overview of each
diagnostic category.
DTC Descriptor
DT