B1738 – Mirror Driver Horizontal Switch Circuit Open

The ODBII code B1738 indicates a malfunction in the horizontal switch circuit of the mirror driver, specifically that the circuit is open, meaning there is a break or disconnection in the electrical path.

The severity of ODBII code B1738 is generally considered moderate.

Common Causes For: B1737 Mirror Driver Horizontal Switch Circuit Failure

• Faulty mirror switch
• Damaged wiring or connectors
• Open circuit in the mirror driver circuit
• Faulty mirror motor
• Corrosion or poor connections in the circuit
• Malfunctioning body control module (BCM)

Common misdiagnosis for B1738 Mirror Driver Horizontal Switch Circuit Open

• Faulty mirror switch
• Wiring issues or shorts
• Defective mirror motor
• Body control module (BCM) failure
• Incorrectly installed or damaged mirror assembly
• Software or programming errors in the vehicle’s computer system

Common Troubleshooting Steps

The OBD-II code B1738 refers to a problem with the mirror driver horizontal switch circuit, indicating that there is an open circuit in the system. Here are some common troubleshooting steps to diagnose and potentially resolve this issue:

• Check the Vehicle’s Manual: Refer to the vehicle’s service manual for specific information about the mirror driver system and wiring diagrams.
• Visual Inspection:
• Inspect the wiring and connectors associated with the mirror switch and the mirror itself for any signs of damage, corrosion, or loose connections.
• Look for frayed wires, broken connectors, or any other physical damage.
• Test the Mirror Switch:
• Use a multimeter to test the mirror switch for continuity. If the switch is faulty, it may need to be replaced.
• Check for proper operation of the switch by manually activating it and observing if the mirror responds accordingly.
• Check the Mirror Motor:
• If the switch is functioning correctly, test the mirror motor for continuity and proper operation. If the motor is faulty, it may need to be replaced.
• Inspect the Circuit:
• Use a multimeter to check for continuity in the wiring between the mirror switch and the mirror motor. Look for any breaks in the circuit.
• Check for any shorts to ground or power that could be affecting the circuit.
• Scan for Additional Codes:
• Use an OBD-II scanner to check for any additional trouble codes that may provide more context or indicate related issues.
• Check Fuses:
• Inspect the fuses related to the mirror system. A blown fuse could cause the circuit to be open.
• Test the Body Control Module (BCM):
• If all other components are functioning correctly, the issue may lie within the BCM. Check for any software updates or faults in the module.
• Clear Codes and Test Drive:
• After performing repairs or replacements, clear the trouble codes using an OBD-II scanner and take the vehicle for a test drive to see if the code returns.
• Consult a Professional:
• If the issue persists after performing these steps, it may be best to consult a professional mechanic or technician who has experience with automotive electrical systems. By following these steps, you should be able to identify and resolve the issue related to the B1738 code.