B1738: Mirror Driver Horizontal Switch Circuit Open

Definition

The OBD2 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

Common causes

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 misdiagnoses

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

Troubleshooting steps

1. Check the Vehicle's Manual

Refer to the vehicle's service manual for specific information about the mirror driver system and wiring diagrams
2. Visual Inspection
3. Inspect the wiring and connectors associated with the mirror switch and the mirror itself for any signs of damage, corrosion, or loose connections
4. Look for frayed wires, broken connectors, or any other physical damage
5. Test the Mirror Switch
6. Use a multimeter to test the mirror switch for continuity. If the switch is faulty, it may need to be replaced
7. Check for proper operation of the switch by manually activating it and observing if the mirror responds accordingly
8. Check the Mirror Motor
9. 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
10. Inspect the Circuit
11. 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
12. Check for any shorts to ground or power that could be affecting the circuit
13. Scan for Additional Codes
14. Use an OBD-II scanner to check for any additional trouble codes that may provide more context or indicate related issues
15. Check Fuses
16. Inspect the fuses related to the mirror system. A blown fuse could cause the circuit to be open
17. Test the Body Control Module (BCM)
18. If all other components are functioning correctly, the issue may lie within the BCM. Check for any software updates or faults in the module
19. Clear Codes and Test Drive
20. 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
21. Consult a Professional
22. 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

Definition

Common causes

Common misdiagnoses

Troubleshooting steps

1. Check the Vehicle's Manual

2. Visual Inspection

3. Inspect the wiring and connectors associated with the mirror switch and the mirror itself for any signs of damage, corrosion, or loose connections

4. Look for frayed wires, broken connectors, or any other physical damage

5. Test the Mirror Switch

6. Use a multimeter to test the mirror switch for continuity. If the switch is faulty, it may need to be replaced

7. Check for proper operation of the switch by manually activating it and observing if the mirror responds accordingly

8. Check the Mirror Motor

9. 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

10. Inspect the Circuit

11. 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

12. Check for any shorts to ground or power that could be affecting the circuit

13. Scan for Additional Codes

14. Use an OBD-II scanner to check for any additional trouble codes that may provide more context or indicate related issues

15. Check Fuses

16. Inspect the fuses related to the mirror system. A blown fuse could cause the circuit to be open

17. Test the Body Control Module (BCM)

18. If all other components are functioning correctly, the issue may lie within the BCM. Check for any software updates or faults in the module

19. Clear Codes and Test Drive

20. 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

21. Consult a Professional

22. 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