Introduction
The B1743 diagnostic trouble code (DTC) indicates a short to battery in the passenger side mirror's vertical (up/down) adjustment switch circuit. This means the circuit, which controls the mirror's vertical movement, is receiving unintended voltage directly from the battery. This can cause the mirror to move unexpectedly, drain the battery, or even damage the mirror motor or associated control modules. Understanding the causes, symptoms, and diagnostic procedures for this code is crucial for efficient troubleshooting and repair.
Comprehensive Table: B1743 Mirror Passenger Vertical Switch Circuit Short To Battery
| Topic | Description | Potential Solutions |
|---|---|---|
| Code Definition | B1743: Mirror Passenger Vertical Switch Circuit Short To Battery. This signifies an unintended voltage supply to the vertical adjustment circuit of the passenger side mirror. | N/A - This is the definition. |
| Common Symptoms | Passenger side mirror moving erratically or not at all, constant operation of the mirror motor, battery drain, blown fuses, mirror switch inoperative or partially operative, possible burnt smell. | Inspect and test the mirror switch, check for blown fuses, trace wiring for shorts, replace the mirror motor if necessary, inspect related control modules. |
| Possible Causes | Shorted wiring in the mirror switch circuit, damaged mirror switch, faulty mirror motor, chafed or damaged wiring harness, water intrusion in connectors, corrosion in connectors, faulty body control module (BCM) or driver door module (DDM). | Inspect wiring and connectors for damage, test the mirror switch, test the mirror motor, replace damaged components, address water intrusion issues, clean corroded connectors. |
| Diagnostic Tools | Multimeter, wiring diagrams for the specific vehicle model, scan tool (capable of reading and clearing DTCs), test light, wire tracing tools. | Gather necessary tools, acquire vehicle-specific wiring diagrams, understand how to use a multimeter, learn how to read electrical schematics. |
| Troubleshooting Steps | Verify the DTC, inspect fuses, inspect the mirror switch, inspect the wiring harness, test the mirror motor, isolate the short to battery, test the BCM/DDM. | Follow a systematic approach, use wiring diagrams to trace circuits, perform voltage and continuity tests, use a process of elimination to identify the source of the short. |
| Fuse Location & Type | Varies by vehicle model; consult the owner's manual or wiring diagrams. Typically a low-amperage fuse (5-10 amps) dedicated to the power mirror circuit. | Locate the relevant fuse, visually inspect for breakage, test the fuse with a multimeter for continuity. Replace with the correct amperage fuse. |
| Mirror Switch Testing | Use a multimeter to test for continuity between the switch terminals in each position (up, down, left, right, center). Compare readings to specifications in the service manual. | Disconnect the switch connector, perform continuity tests, check for short circuits between terminals, replace the switch if it fails testing. |
| Wiring Harness Inspection | Visually inspect the wiring harness for chafing, cuts, or damage. Pay close attention to areas where the harness passes through the door jamb or near moving parts. | Repair or replace damaged wiring, use electrical tape or heat shrink tubing to protect repaired wires, secure the wiring harness to prevent future damage. |
| Mirror Motor Testing | Apply direct voltage to the mirror motor terminals to verify its operation. Use a multimeter to check for continuity between the motor terminals and ground. | Disconnect the motor connector, apply voltage (typically 12V) to the terminals, check for movement, test for shorts to ground, replace the motor if it fails testing. |
| BCM/DDM Testing | Requires advanced diagnostic equipment and procedures. Usually involves checking for proper voltage and ground at the module, and monitoring communication signals. | Consult a qualified technician for BCM/DDM testing and diagnosis. These modules are complex and require specialized knowledge and equipment. |
| Related DTCs | B1742 (Mirror Passenger Horizontal Switch Circuit Short To Battery), other power mirror circuit codes, body control module (BCM) communication errors. | Address all related DTCs to ensure a complete and accurate diagnosis. Intermittent problems in other systems can sometimes trigger seemingly unrelated codes. |
| Safety Precautions | Disconnect the battery before working on electrical circuits. Use appropriate safety glasses and gloves. Be careful when working with sharp tools. | Prioritize safety, disconnect the battery to prevent electrical shock, wear protective gear, work in a well-lit area. |
| Estimated Repair Cost | Varies widely depending on the cause of the problem. A simple wiring repair might cost $50-$100, while replacing a mirror motor or BCM could cost several hundred dollars. | Obtain an accurate estimate from a qualified mechanic before authorizing any repairs. Ask for a breakdown of parts and labor costs. |
Detailed Explanations
Code Definition: The B1743 code specifically points to a problem within the electrical circuit responsible for controlling the vertical movement (up and down) of the passenger side mirror. The "short to battery" designation indicates that a wire or component in this circuit is making unintended contact with a positive voltage source (typically the vehicle's battery), resulting in excessive current flow.
Common Symptoms: When the B1743 code is present, you might notice the passenger side mirror moving on its own, failing to respond to the switch, or exhibiting intermittent movement. A constant draw on the battery due to the short can lead to a dead battery, especially if the vehicle sits unused for extended periods. You might also observe blown fuses related to the power mirror circuit, or even a burning smell originating from the mirror switch or motor.
Possible Causes: The most common cause is damaged wiring, where the insulation has worn away, exposing the wire and allowing it to touch metal parts of the vehicle. A faulty mirror switch can internally short to battery. A defective mirror motor can also cause a short. Water intrusion or corrosion in connectors can create conductive paths, leading to a short. In rare cases, a malfunctioning BCM or DDM could be the culprit.
Diagnostic Tools: A multimeter is essential for measuring voltage, resistance, and continuity in the circuit. Wiring diagrams are crucial for understanding the circuit layout and identifying the correct wires to test. A scan tool can read and clear the B1743 code and other related codes. A test light is helpful for quickly checking for voltage at various points in the circuit. Wire tracing tools, like a tone generator and probe, can help locate specific wires within a harness.
Troubleshooting Steps: Start by verifying the B1743 code with a scan tool. Then, inspect the fuses related to the power mirror circuit. Next, inspect the mirror switch for damage or signs of water intrusion. Carefully inspect the wiring harness leading to the mirror for any signs of chafing or damage. Test the mirror motor directly by applying voltage. The most challenging step is to isolate the short to battery by systematically disconnecting components and testing for continuity to ground. Finally, if all else fails, test the BCM/DDM.
Fuse Location & Type: Refer to your vehicle's owner's manual or a wiring diagram to find the specific fuse for the power mirror circuit. These fuses are typically located in the fuse box under the dashboard or in the engine compartment. The amperage rating is usually low, around 5-10 amps. Using a fuse with a higher amperage rating can be dangerous and could damage the electrical system.
Mirror Switch Testing: Disconnect the mirror switch connector and use a multimeter set to measure continuity. By testing each position of the switch (up, down, left, right, center), you can determine if the switch is functioning correctly. Compare your readings to the specifications in the vehicle's service manual.
Wiring Harness Inspection: Carefully examine the wiring harness that runs from the mirror switch to the mirror motor and the BCM/DDM. Pay close attention to areas where the harness passes through the door jamb, as this is a common spot for chafing. Look for any signs of cuts, abrasions, or corrosion.
Mirror Motor Testing: Disconnect the mirror motor connector and apply direct voltage (usually 12V) to the motor terminals. The mirror should move in the corresponding direction. If the motor doesn't move, or if it makes unusual noises, it may be faulty. Also, test for a short to ground by checking for continuity between the motor terminals and the mirror housing.
BCM/DDM Testing: Testing these modules requires specialized diagnostic equipment and expertise. It's best to consult a qualified technician for BCM/DDM testing. They can use a scan tool to monitor the module's communication signals and check for proper voltage and ground.
Related DTCs: The presence of other DTCs, such as B1742 (Mirror Passenger Horizontal Switch Circuit Short To Battery) or BCM communication errors, can provide valuable clues about the root cause of the B1743 code. Addressing all related DTCs is crucial for a complete and accurate diagnosis.
Safety Precautions: Always disconnect the negative battery terminal before working on any electrical circuits. Wear safety glasses and gloves to protect your eyes and hands. Be careful when using sharp tools to avoid injury.
Estimated Repair Cost: The cost of repairing a B1743 code can vary widely depending on the cause of the problem. A simple wiring repair might cost $50-$100, while replacing a mirror motor or BCM could cost several hundred dollars or more. Always obtain an accurate estimate from a qualified mechanic before authorizing any repairs.
Frequently Asked Questions
What does the B1743 code mean? It indicates a short to battery in the passenger side mirror's vertical adjustment circuit, meaning the circuit is receiving unintended voltage.
What are the common symptoms of B1743? Erratic mirror movement, battery drain, blown fuses, or a non-functional mirror are common signs.
How do I find the fuse for the power mirrors? Consult your vehicle's owner's manual or a wiring diagram for the fuse location.
Can I fix this problem myself? Depending on your mechanical and electrical skills, you might be able to fix simple wiring issues. However, more complex problems may require a qualified technician.
How much will it cost to fix B1743? The cost can vary widely depending on the cause, ranging from a simple wiring repair to replacing the mirror motor or BCM.
Conclusion
The B1743 code indicates a potentially serious electrical problem in the passenger side mirror circuit. Through careful diagnosis and systematic troubleshooting, the root cause of the short to battery can be identified and repaired, restoring proper mirror function and preventing further damage to the vehicle's electrical system. It is important to follow safety precautions and seek professional help if you are not comfortable working with electrical circuits.