B1739 – OBD-II DTC

OBD-II DTC B1739 – Mirror Driver Horizontal Switch Circuit Short To Battery

DTC B1739 meaning

DTC B1739 refers to a diagnostic trouble code indicating a short circuit in the driver horizontal switch circuit of the vehicle’s mirror system. This code is triggered when the vehicle’s onboard diagnostic system detects that the horizontal switch for the driver’s side mirror is shorted to battery voltage, which can prevent proper mirror adjustment functionality.

DTC B1739 symptoms

Common symptoms associated with DTC B1739 may include:

• The driver’s side mirror may not adjust horizontally.
• Mirror adjustment controls may be unresponsive.
• Other electrical issues in the vehicle may arise due to the short circuit.
• Dashboard warning lights may illuminate.

DTC B1739 causes

Several factors can lead to the occurrence of DTC B1739, including:

• A faulty horizontal switch in the driver’s side mirror.
• Wiring issues, such as frayed or damaged wires.
• Corrosion or poor connections in the mirror adjustment circuit.
• Short circuits caused by moisture intrusion or foreign objects.

DTC B1739 seriousness

DTC B1739 is considered a moderate issue. While it may not affect the vehicle’s overall drivability, it can hinder the driver’s ability to adjust the side mirror, which is crucial for safe driving. Ignoring this code may lead to further electrical problems or damage to the mirror adjustment system.

How to diagnose DTC B1739

To diagnose DTC B1739, follow these steps:

1. Use an OBD-II scanner to confirm the presence of the B1739 code.
2. Inspect the driver’s side mirror switch for physical damage or wear.
3. Check the wiring and connectors for signs of corrosion or damage.
4. Test the horizontal switch for continuity using a multimeter.
5. Examine the vehicle’s wiring harness for shorts to battery voltage.

How to fix DTC B1739 step-by-step instructions

To fix DTC B1739, follow these steps:

1. Disconnect the vehicle’s battery to ensure safety while working on the electrical system.
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 for any shorts or damaged wires and repair or replace as needed.
5. Reconnect all connectors and ensure they are secure.
6. Reinstall the driver’s side mirror switch and reconnect the battery.
7. Use the OBD-II scanner to clear the DTC and test the mirror adjustment functionality.

How to erase DTC B1739

To erase DTC B1739, follow these steps:

1. Connect an OBD-II scanner to the vehicle’s diagnostic port.
2. Turn on the vehicle’s ignition without starting the engine.
3. Navigate to the “Erase Codes” or “Clear DTCs” option on the scanner.
4. Confirm the action to clear the trouble codes.
5. Disconnect the scanner and start the vehicle to ensure the code does not reappear.

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