The B1736 error code, indicating a "Mirror Driver Vertical Switch Circuit Short To Ground," is a diagnostic trouble code (DTC) commonly encountered in modern vehicles, particularly those with advanced electronic mirror control systems. This code signifies a fault within the electrical circuit responsible for the vertical adjustment of one or more of the vehicle's side mirrors. Addressing this issue promptly is important for maintaining proper visibility and safe driving conditions.
This article will delve into the intricacies of the B1736 code, exploring its causes, symptoms, diagnostic procedures, and potential solutions. We'll provide a comprehensive understanding of the system involved, enabling both DIY enthusiasts and professional technicians to effectively troubleshoot and resolve this problem.
| Topic | Description | Possible Causes |
|---|---|---|
| Mirror Driver Module (MDM) | The electronic control unit (ECU) responsible for controlling the movement of the side mirrors. It receives input from the mirror adjustment switch and sends signals to the mirror motors. It also monitors the circuit for faults. A malfunctioning MDM may incorrectly interpret the signals and erroneously set the B1736 code. | Internal MDM failure, corrosion on MDM connectors, software glitches, incorrect MDM programming. |
| Mirror Adjustment Switch | The physical switch inside the vehicle that allows the driver to adjust the position of the side mirrors. A faulty switch can send incorrect or erratic signals to the MDM, leading to the B1736 code. A short circuit within the switch itself can also trigger the code. | Internal switch failure, short circuit within the switch, corrosion on switch connectors, mechanical damage to the switch. |
| Mirror Motor(s) | The electric motors located within the side mirror housings that physically move the mirror glass vertically. A short circuit within the motor winding or a mechanical problem that causes excessive current draw can trigger the B1736 code. Binding or resistance within the mirror mechanism can also overload the motor circuit. | Internal motor short circuit, binding or obstruction in the mirror mechanism, excessive motor wear, corrosion within the motor housing. |
| Wiring Harness and Connectors | The wires and connectors that connect the MDM, mirror adjustment switch, and mirror motors. Damage to the wiring, such as frayed wires or corroded connectors, can cause a short circuit to ground, triggering the B1736 code. This is often the most common cause. | Damaged wiring insulation, frayed wires, corroded connectors, loose connectors, pinched wires, rodent damage. |
| Ground Circuit | The path through which electrical current returns to the vehicle's battery. A poor or missing ground connection can cause the MDM to misinterpret signals and set the B1736 code. A short to ground in the mirror circuit will directly affect this. | Corroded ground connection, loose ground connection, broken ground wire. |
| Fuse/Circuit Breaker | Protects the mirror circuit from overcurrent. While a blown fuse could be related, it's less likely to be the direct cause of the B1736. More often, a short circuit causes the fuse to blow. Repeatedly replacing a blown fuse without addressing the underlying short circuit will likely lead to further damage. | Blown fuse (more likely a symptom than a direct cause), incorrect fuse rating. |
| Diagnostic Tools | Scan tools, multimeters, and wiring diagrams are essential for diagnosing the B1736 code. A scan tool can retrieve the code and provide additional information about the system. A multimeter can be used to test the continuity and voltage of the wiring and components. Wiring diagrams are necessary to understand the circuit layout and identify the correct test points. | Improper use of diagnostic tools, outdated software, incorrect wiring diagrams. |
| Symptoms | The most common symptom is the inability to adjust the side mirrors vertically. Other symptoms may include intermittent mirror operation, mirror moving erratically, or a blown fuse. The diagnostic trouble code (DTC) B1736 will also be present. | N/A |
| Troubleshooting Steps | The troubleshooting process typically involves verifying the code, inspecting the wiring and connectors, testing the mirror adjustment switch, testing the mirror motors, and testing the MDM. | Skipping steps, incorrect testing procedures, neglecting visual inspection. |
| Repair Procedures | Repair procedures may include repairing or replacing damaged wiring, cleaning or replacing corroded connectors, replacing the mirror adjustment switch, replacing the mirror motors, or replacing the MDM. | Incorrect repair procedures, using incorrect parts, failing to properly secure connections. |
Detailed Explanations:
Mirror Driver Module (MDM): The Mirror Driver Module is the brain of the mirror control system. It takes input from the mirror adjustment switch, interprets these signals, and then sends commands to the mirror motors to move the mirror glass. The MDM also monitors the electrical circuit for any faults, such as a short to ground or an open circuit. If the MDM detects a problem, it will store a diagnostic trouble code, such as B1736, in its memory. Internal failures, connector corrosion, and software issues can all cause MDM malfunctions.
Mirror Adjustment Switch: This is the physical control used by the driver to adjust the mirrors. It typically has a multi-directional switch for selecting the mirror (left or right) and then another control (often a 4-way rocker switch) for adjusting the mirror up/down and left/right. The switch sends signals to the MDM based on the driver's input. A faulty switch can send incorrect or no signals, leading to improper mirror operation and potentially triggering the B1736 code. A short circuit within the switch itself is a common cause.
Mirror Motor(s): These small electric motors are located inside the mirror housings. They are responsible for physically moving the mirror glass in response to commands from the MDM. Each mirror typically has two motors: one for vertical adjustment and one for horizontal adjustment. A short circuit within the motor windings, caused by insulation breakdown or physical damage, can draw excessive current and trigger the B1736 code. Mechanical binding within the mirror mechanism can also overload the motor, leading to a similar result.
Wiring Harness and Connectors: The wiring harness and connectors provide the electrical pathways connecting all components of the mirror control system. This includes the MDM, the mirror adjustment switch, and the mirror motors. Damage to the wiring, such as cuts, abrasions, or corrosion, can create short circuits to ground. Connectors can also become corroded or loose, disrupting the electrical connection and causing intermittent problems or a complete failure of the system. Inspect these carefully, paying particular attention to areas where the wiring harness passes through the door jamb, as this is a common area for damage.
Ground Circuit: A solid ground connection is essential for the proper operation of any electrical system. The ground circuit provides a return path for electrical current to the vehicle's battery. A poor or missing ground connection can cause the MDM to misinterpret signals, leading to incorrect operation and potentially triggering false diagnostic codes. Ensure the ground connection for the MDM and the mirror motors are clean, tight, and free of corrosion.
Fuse/Circuit Breaker: The fuse or circuit breaker is a safety device designed to protect the mirror circuit from overcurrent. If a short circuit occurs, the fuse will blow, interrupting the flow of electricity and preventing damage to other components. While a blown fuse is often a symptom of the problem (the short circuit), it can also be a contributing factor if the fuse is repeatedly replaced without addressing the underlying issue. Repeatedly blowing fuses indicates a persistent short circuit that needs to be located and repaired.
Diagnostic Tools: Proper diagnosis requires the use of appropriate diagnostic tools. A scan tool is essential for retrieving the B1736 code and any other related DTCs. A multimeter is necessary for testing the continuity and voltage of the wiring and components. Wiring diagrams are crucial for understanding the circuit layout and identifying the correct test points. Understanding how to use these tools correctly is vital for accurate diagnosis.
Symptoms: The most obvious symptom of the B1736 code is the inability to adjust the side mirrors vertically. Other symptoms may include intermittent mirror operation, erratic mirror movement, or a blown fuse. The presence of the B1736 DTC, retrieved using a scan tool, confirms a problem within the mirror control circuit. Note that the symptom may only affect one mirror, or both, depending on the location of the fault.
Troubleshooting Steps: A systematic approach to troubleshooting is essential for resolving the B1736 code. This typically involves the following steps:
- Verify the Code: Use a scan tool to confirm the presence of the B1736 code and any other related DTCs.
- Inspect Wiring and Connectors: Visually inspect the wiring harness and connectors for any signs of damage, corrosion, or loose connections. Pay particular attention to areas where the wiring passes through the door jamb.
- Test Mirror Adjustment Switch: Use a multimeter to test the continuity and resistance of the mirror adjustment switch. Refer to a wiring diagram to identify the correct test points.
- Test Mirror Motors: Disconnect the mirror motors and use a multimeter to test their resistance. A shorted motor will typically have a very low resistance reading. Also, check for voltage at the motor connector when the adjustment switch is activated.
- Test MDM: Testing the MDM often requires specialized equipment and procedures. If you suspect the MDM is faulty, it is best to consult a qualified technician.
- Check Ground Connections: Ensure the ground connections for the MDM and the mirror motors are clean, tight, and free of corrosion.
Repair Procedures: Once the cause of the B1736 code has been identified, the appropriate repair procedure can be performed. This may involve repairing or replacing damaged wiring, cleaning or replacing corroded connectors, replacing the mirror adjustment switch, replacing the mirror motors, or replacing the MDM. Ensure that all repairs are performed correctly and that all connections are properly secured.
Frequently Asked Questions:
What does the B1736 code mean? It indicates a short to ground in the vertical switch circuit of the mirror driver. This means there's an unintended electrical connection to the vehicle's chassis ground.
Can I fix the B1736 code myself? Potentially, if you have basic electrical knowledge and tools like a multimeter. Start with visual inspection of wiring and connectors.
What tools do I need to diagnose the B1736 code? A scan tool to read the code, a multimeter to test circuits, and wiring diagrams are essential.
Could a bad mirror motor cause the B1736 code? Yes, a shorted internal to the motor winding can cause a short to ground within the mirror circuit.
How do I check the wiring for a short to ground? Use a multimeter in continuity mode. With the circuit de-energized, check for continuity between the wire and a known good ground point on the vehicle.
Conclusion:
The B1736 "Mirror Driver Vertical Switch Circuit Short To Ground" code requires a systematic approach to diagnose and repair. By understanding the components involved, performing thorough inspections, and using the appropriate diagnostic tools, you can effectively resolve this issue and restore proper mirror functionality. Always prioritize safety and consult a qualified technician if you are unsure about any aspect of the repair process.