B1779 – Mirror Driver Down Circuit Open

The ODBII code B1779 indicates a fault in the mirror driver circuit, specifically that the circuit is open, meaning there is a break or disconnection preventing proper operation of the mirror adjustment system.

The severity of ODBII code B1779 is generally considered moderate.

Common Causes For: B1778 Mirror Driver Down Circuit Failure

• Faulty mirror driver module
• Open circuit in wiring harness
• Corroded or damaged connectors
• Short circuit in the mirror driver circuit
• Faulty mirror motor
• Blown fuse related to the mirror system
• Poor ground connection
• Malfunctioning body control module (BCM)

Common misdiagnosis for B1779 Mirror Driver Down Circuit Open

• Faulty mirror switch
• Wiring harness issues
• Defective mirror motor
• Malfunctioning body control module (BCM)
• Poor ground connections
• Incorrectly installed or damaged mirror assembly
• Software or programming errors in the vehicle’s computer system

Common Troubleshooting Steps

The OBD-II code B1779 indicates a problem with the mirror driver circuit, specifically that the circuit is open. This can affect the operation of the power mirrors in your vehicle. Here are some common troubleshooting steps to diagnose and potentially resolve the issue:

• Check the Vehicle’s Manual: Refer to the vehicle’s service manual for specific information regarding the mirror driver circuit and wiring diagrams.
• Visual Inspection:
• Inspect the wiring harness and connectors associated with the mirror assembly for any signs of damage, corrosion, or loose connections.
• Look for frayed wires or broken connectors that could cause an open circuit.
• Check the Mirror Assembly:
• If the vehicle has power mirrors, ensure that the mirror assembly itself is not damaged. Sometimes, the internal components can fail.
• Test the Mirror Switch:
• The mirror control switch can also be a source of the problem. Test the switch for continuity and proper operation. If the switch is faulty, it may need to be replaced.
• Check Fuses:
• Inspect the fuses related to the power mirrors. A blown fuse can interrupt the circuit and cause the B1779 code to set.
• Use a Multimeter:
• Use a multimeter to check for continuity in the mirror driver circuit. This will help identify if there is an open circuit somewhere in the wiring.
• Measure the voltage at the mirror connector while operating the mirror switch to ensure that power is reaching the mirror.
• Scan Tool Diagnosis:
• Use an OBD-II scanner to check for any additional codes that may provide more context to the issue.
• Clear the code and see if it returns after performing the above checks.
• Inspect Ground Connections:
• Ensure that the ground connections for the mirror circuit are secure and free of corrosion. A poor ground can lead to circuit issues.
• Check for Short Circuits:
• Look for any short circuits in the wiring that could affect the mirror driver circuit.
• Consult a Professional:
• If the issue persists after performing these steps, it may be best to consult a professional mechanic or an automotive electrician for further diagnosis. By following these steps, you should be able to identify the cause of the B1779 code and take appropriate action to resolve the issue.