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.

• If 10 Ω or greater

1. Ignition OFF.
2. 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

1. Ignition OFF, remove the test lamp.
2. 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

1. Ignition OFF, remove the test lamp.
2. 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
3. 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

1. Ignition OFF, remove the test lamp, disconnect the harness connector at the S146 Outside Rearview Mirror Switch.
2. 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
3. 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

1. Ignition OFF, remove the test lamp, disconnect the harness connector at the S146 Outside Rearview Mirror Switch, ignition ON.
2. 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

1. Ignition OFF, remove the test lamp, disconnect the harness connector at the S146 Outside Rearview Mirror Switch.
2. 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
3. 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

1. Ignition OFF, remove the test lamp, disconnect the harness connector at the S146 Outside Rearview Mirror Switch, ignition ON.
2. 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.

• If 10 Ω or greater

1. Ignition OFF, disconnect the harness connector at the S146 Outside Rearview Mirror Switch.
2. 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.

• If less than 4.8 V

1. Ignition OFF, disconnect the harness connector at the S146 Outside Rearview Mirror Switch.
2. 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
3. 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.

• If greater than 5.2 V

1. Ignition OFF, disconnect the harness connector at the S146 Outside Rearview Mirror Switch, ignition ON.
2. 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.

• If 4.6 V or greater

1. Ignition OFF, disconnect the harness connector at the S146 Outside Rearview Mirror Switch, ignition ON.
2. 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.

• If 0.6 V or less

1. Ignition OFF, remove the jumper wire, disconnect the harness connector at the S146 Outside Rearview Mirror Switch.
2. 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
3. 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.

• If 4.6 V or greater

1. Ignition OFF, disconnect the harness connector at the S146 Outside Rearview Mirror Switch, ignition ON.
2. 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.

• If 0.6 V or less

1. Ignition OFF, remove the jumper wire, disconnect the harness connector at the S146 Outside Rearview Mirror Switch.
2. 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
3. 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

1. Ignition OFF, remove the test lamp, disconnect the X2 harness connector at the S79P Window Switch-Passenger.
2. 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
3. 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

1. Ignition OFF, remove the test lamp, disconnect the X2 harness connector at the S79P Window Switch-Passenger, ignition ON.
2. 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

1. Ignition OFF, remove the test lamp, disconnect the X2 harness connector at the S79P Window Switch-Passenger.
2. 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
3. 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

1. Ignition OFF, remove the test lamp, disconnect the X2 harness connector at the S79P Window Switch-Passenger, ignition ON.
2. 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.

• If 10 Ω or greater

1. Ignition OFF, disconnect the X2 harness connector at the S79P Window Switch-Passenger.
2. 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.

• If less than 4.8 V

1. Ignition OFF, disconnect the X2 harness connector at the S79P Window Switch-Passenger.
2. 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
3. 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.

• If greater than 5.2 V

1. Ignition OFF, disconnect the X2 harness connector at the S79P Window Switch-Passenger, ignition ON.
2. 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.

• If 4.6 V or greater

1. Ignition OFF, disconnect the X2 harness connector at the S79P Window Switch-Passenger, ignition ON.
2. 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.

• If 0.6 V or less

1. Ignition OFF, remove the jumper wire, disconnect the X2 harness connector at the S79P Window Switch-Passenger.
2. 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
3. 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.

• If 4.6 V or greater

1. Ignition OFF, disconnect the X2 harness connector at the S79P Window Switch-Passenger, ignition ON.
2. 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.

• If 0.6 V or less

1. Ignition OFF, remove the jumper wire, disconnect the X2 harness connector at the S79P Window Switch-Passenger.
2. 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
3. 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

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