B1738 – OBD-II DTC

OBD-II DTC B1738 – Mirror Driver Horizontal Switch Circuit Open

DTC B1738 meaning

DTC B1738 refers to a diagnostic trouble code indicating an issue with the driver’s side mirror horizontal switch circuit. This code is triggered when the vehicle’s onboard diagnostic system detects an open circuit in the switch that controls the horizontal movement of the driver’s side mirror. The open circuit can prevent the mirror from adjusting properly, affecting visibility and safety.

DTC B1738 symptoms

Common symptoms associated with DTC B1738 may include:

• Inability to adjust the driver’s side mirror horizontally
• Mirror position remains fixed
• Warning lights on the dashboard related to mirror adjustments
• Intermittent functionality of the mirror adjustment switch

DTC B1738 causes

Several factors can lead to the triggering of DTC B1738, including:

• Faulty mirror horizontal switch
• Damaged wiring or connectors in the switch circuit
• Corrosion or poor connections at the switch or mirror assembly
• Issues with the body control module (BCM) that manages mirror functions

DTC B1738 seriousness

The seriousness of DTC B1738 can vary, but it is generally considered a moderate issue. While it may not immediately affect the vehicle’s drivability, it can compromise the driver’s ability to adjust the mirror for optimal visibility, which is crucial for safe driving. Addressing this code promptly is recommended to ensure proper mirror functionality.

How to diagnose DTC B1738

To diagnose DTC B1738, follow these steps:

1. Use an OBD-II scanner to confirm the presence of the B1738 code.
2. Inspect the driver’s side mirror switch for physical damage or wear.
3. Check the wiring and connectors for signs of corrosion, fraying, or disconnection.
4. Test the continuity of the switch circuit using a multimeter.
5. Examine the body control module for any related fault codes or issues.

How to fix DTC B1738 step-by-step instructions

To fix DTC B1738, follow these step-by-step instructions:

1. Disconnect the vehicle’s battery to ensure safety while working on electrical components.
2. Remove the driver’s side mirror switch from the vehicle.
3. Inspect the switch for damage and replace it if necessary.
4. Check the wiring harness and connectors for any signs of damage or corrosion repair or replace as needed.
5. Reconnect the switch and ensure all connections are secure.
6. Reconnect the vehicle’s battery.
7. Use the OBD-II scanner to clear the DTC and test the mirror adjustment functionality.

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