B1639 – Mirror Passenger Left Circuit Failure

The ODBII code B1639 indicates a malfunction in the passenger side mirror circuit, specifically a failure in the left mirror’s electrical system or wiring.

The severity of ODBII code B1639 is moderate.

Common Causes For: B1638 Mirror Driver Right Short To Ground

• Faulty passenger side mirror assembly
• Damaged wiring or connectors in the mirror circuit
• Blown fuse related to the mirror system
• Malfunctioning mirror control switch
• Short circuit in the wiring harness
• Corrosion or poor connections at the terminals
• Failed body control module (BCM) or related control module

Common misdiagnosis for B1639 Mirror Passenger Left Circuit Failure

• Faulty passenger side mirror
• Wiring issues in the mirror circuit
• Malfunctioning body control module (BCM)
• Defective switch or control module for the mirror
• Grounding issues in the electrical system
• Short circuit in the wiring harness
• Faulty relay related to the mirror operation
• Incorrectly installed or damaged mirror assembly

Common Troubleshooting Steps

The OBD-II code B1639 indicates a “Mirror Passenger Left Circuit Failure.” This code typically relates to issues with the electrical circuit that controls the left passenger side mirror. Here are some common troubleshooting steps to diagnose and potentially resolve the issue:

• Check for Additional Codes: Use an OBD-II scanner to check for any other related trouble codes. This can provide more context and help identify if there are multiple issues.
• Inspect the Wiring and Connectors:
• Visually inspect the wiring harness and connectors leading to the left passenger side mirror. Look for any signs of damage, corrosion, or loose connections.
• Ensure that the connectors are securely attached and that there are no bent pins.
• Test the Mirror Functionality:
• Manually adjust the mirror using the control switch. If the mirror does not respond, it may indicate a problem with the switch or the mirror itself.
• If the mirror has heating or other features, test those functions as well.
• Check the Control Switch:
• Test the mirror control switch for proper operation. You can do this by checking for continuity with a multimeter when the switch is activated.
• If the switch is faulty, it may need to be replaced.
• Inspect the Mirror Assembly:
• If the wiring and switch are functioning correctly, the issue may lie within the mirror assembly itself. Check for any internal faults in the mirror motor or heating element (if applicable).
• Test for Power and Ground:
• Use a multimeter to check for power and ground at the mirror connector. Ensure that the mirror is receiving the correct voltage when the control switch is activated.
• If there is no power or ground, trace the wiring back to the source to identify any breaks or shorts.
• Check for Short Circuits:
• Inspect the circuit for any short circuits that may be causing the failure. This can include checking for damaged insulation or pinched wires.
• Consult Wiring Diagrams:
• Refer to the vehicle’s wiring diagrams to understand the circuit layout and identify any other components that may be involved in the mirror operation.
• Reset the Code:
• After performing any repairs, clear the trouble code using the OBD-II scanner and take the vehicle for a test drive to see if the code returns.
• Seek Professional Help:
• If the issue persists after performing these steps, it may be necessary to consult a professional mechanic or an automotive electrician for further diagnosis and repair. By following these steps, you should be able to identify the cause of the B1639 code and take appropriate action to resolve the issue.