GM Service Manual Online
For 1990-2009 cars only

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 Descriptors

DTC B1544 01: Mirror Motors Common Circuit Short to Battery

DTC B1544 02: Mirror Motors Common Circuit Short to Ground

DTC B1544 04: Mirror Motors Common Circuit Open

DTC B1600 01: Mirror Motor Vertical Circuit Short to Battery

DTC B1600 02: Mirror Motor Vertical Circuit Short to Ground

DTC B1600 04: Mirror Motor Vertical Circuit Open

DTC B1605 01: Mirror Motor Horizontal Circuit Short to Battery

DTC B1605 02: Mirror Motor Horizontal Circuit Short to Ground

DTC B1605 04: Mirror Motor Horizontal Circuit Open

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Driver/Passenger Mirror Motor Horizontal Control

B1605 02

B1605 04

B1605 01

--

Driver/Passenger Mirror Motor Common Control

B1544 02

B1544 04

B1544 01

--

Driver/Passenger Mirror Motor Vertical Control

B1600 02

B1600 04

B1600 01

--

Circuit/System Description

The Driver Door Module (DDM) or Passenger Door Module (PDM) controls the mirror horizontal and vertical motors through the use of bi-directional motor controls. When the mirror is commanded up and down, voltage or ground is supplied to the mirror vertical motor through the mirror motor vertical control circuit and voltage or ground is supplied through the mirror motor common control circuit.

Horizontal controls operate in the same manner with the mirror motor horizontal control circuit supplying voltage or ground and the mirror motor common control circuit suppling voltage or ground to the mirror horizontal motor when the mirror is commanded right and left.

Conditions for Running the DTC

Battery voltage must be between 9-16 volts.

Conditions for Setting the DTC

B1544

An improper voltage level is detected on the driver/passenger mirror motor common control circuit.

B1600

An improper voltage level is detected on the driver/passenger mirror motor vertical control circuit.

B1605

An improper voltage level is detected on the driver/passenger mirror motor horizontal control circuit.

Action Taken When the DTC Sets

Mirror movement is suspended as long as the fault is present.

Conditions for Clearing the DTC

    • A current DTC will clear when the fault is no longer present.
    • A history DTC will clear after 40 malfunction-free ignition cycles.

Reference Information

Schematic Reference

Outside Rearview Mirror Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Outside Mirror Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool References

Control Module References for scan tool information.

Circuit/System Verification

Command the left and right outside mirror to move up, down, left and right using the mirror directional switch. The mirror should move in the commanded direction.

Circuit/System Testing

  1. Ignition OFF, disconnect the X3 harness connector at the appropriate door module.
  2. Ignition ON, verify a test lamp does not illuminate between the following control circuit terminals and ground:
  3. • Control circuit terminal 1
    • Control circuit terminal 2
    • Control circuit terminal 6
    If the test lamp illuminates, test the appropriate control circuit for a short to voltage.
  4. Ignition OFF, test for infinite resistance between the following control circuits and ground:
  5. • Control circuit terminal 1
    • Control circuit terminal 2
    • Control circuit terminal 6
    If less the specified value, test the appropriate control circuit for a short to ground.
  6. Test for 40-100 ohms between the control circuit terminal 1 and the control circuit terminal 6.
  7. If not within the specified range, test both control circuits for an open/high resistance. If the circuits test normal, test or replace the rearview mirror motor.
  8. Test for 40-100 ohms between the control circuit terminal 2 and the control circuit terminal 6.
  9. If not within the specified range, test both control circuits for an open/high resistance. If the circuits test normal, test or replace the rearview mirror motor.
  10. If all circuits test normal, replace the door module.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Outside Rearview Mirror Replacement
    •  Control Module References for DDM or PDM replacement, setup, and programming