The B1747 diagnostic trouble code (DTC) indicates a problem within the passenger side mirror's horizontal adjustment circuit. Specifically, it signifies a short to battery condition within the circuit controlling the mirror's left/right movement. This can prevent the mirror from adjusting horizontally and may even cause other electrical issues. Addressing this issue promptly is crucial to restore full mirror functionality and prevent potential damage to other components.
Here's a comprehensive guide to understanding, diagnosing, and potentially resolving the B1747 DTC.
| Topic | Description | Potential Solutions |
|---|---|---|
| DTC Definition | Passenger Side Mirror Horizontal (Left/Right) Adjustment Circuit Short to Battery. | N/A - Definition only. |
| Affected Systems | Power Mirror System, Vehicle Body Control Module (BCM), Related Wiring Harnesses. | N/A - Identifying affected systems. |
| Symptoms | Passenger side mirror will not adjust horizontally (left/right). Possible fuse blowing. Other electrical malfunctions. | Repair short circuit, replace blown fuses. |
| Possible Causes | Shorted wiring in the mirror motor circuit. Faulty passenger side mirror switch. Defective passenger side mirror motor. Damaged wiring harness. Faulty BCM (less likely). | Inspect wiring, replace switch, replace motor, repair harness, reprogram or replace BCM (as last resort). |
| Diagnostic Tools | Multimeter, Wiring Diagram, Scan Tool (OBD2 scanner). | Use tools to locate short, test components, and clear codes. |
| Fuse Location | Consult vehicle's owner's manual or wiring diagram. Typically located in the interior fuse box or under the hood. | Locate and inspect the fuse associated with the power mirror system. Replace if blown. |
| Wiring Diagram Importance | Crucial for identifying circuit paths and testing points. | Obtain the specific wiring diagram for your vehicle's year, make, and model. |
| Testing Procedures | Voltage testing, Continuity testing, Resistance testing. | Use multimeter to perform tests and isolate the short. |
| Mirror Switch Testing | Check for proper voltage and continuity at the switch terminals. | Refer to wiring diagram and test procedures to confirm switch functionality. |
| Mirror Motor Testing | Apply voltage directly to the motor to check for operation. Check for shorts in the motor windings. | Disconnect the motor from the circuit before applying voltage. Observe motor operation and check for excessive current draw. |
| BCM Involvement | BCM controls power distribution and may be affected by a short in the mirror circuit. | Check BCM for proper operation and connectivity. This is typically a last resort diagnosis. |
| Related DTCs | Other DTCs related to power mirrors or body control functions. | Diagnose and address any related DTCs before focusing solely on B1747. |
| Potential Risks | Electrical fire, damage to BCM, malfunctioning mirror. | Address the issue promptly to prevent further damage. |
| Repair Difficulty | Moderate, depending on the location and complexity of the short. | Consider professional help if you are not comfortable with electrical troubleshooting. |
| Parts Cost | Varies depending on the component needing replacement (switch, motor, wiring harness). | Research prices for replacement parts before starting the repair. |
| Labor Cost | Varies depending on the complexity of the repair and the shop's hourly rate. | Obtain quotes from multiple shops before authorizing repairs. |
| Common Mistakes | Failing to properly diagnose the root cause. Replacing parts without proper testing. Ignoring related DTCs. | Thoroughly diagnose the issue before replacing parts. Use proper testing procedures. |
Detailed Explanations:
DTC Definition: The B1747 code indicates a "Short to Battery" condition within the circuit responsible for moving the passenger side mirror horizontally (left and right). This means that the circuit is receiving unintended voltage directly from the vehicle's battery, potentially bypassing the intended control mechanisms.
Affected Systems: The primary system affected is the power mirror system. However, a short to battery can also impact the Body Control Module (BCM), which manages various electrical functions, and the wiring harnesses that connect these components. Damage or malfunction in one area can lead to problems in others.
Symptoms: The most obvious symptom is the passenger side mirror not adjusting horizontally. You may also experience a blown fuse related to the power mirror circuit. In severe cases, other electrical malfunctions might occur due to the short circuit affecting other vehicle systems.
Possible Causes: Several issues can trigger the B1747 code. A shorted wiring in the mirror motor circuit is a common culprit, often caused by damaged insulation. A faulty passenger side mirror switch can also create a short. Less frequently, a defective passenger side mirror motor or a damaged wiring harness can be the source of the problem. While less likely, a faulty BCM could also contribute.
Diagnostic Tools: You'll need a few essential tools for diagnosing the B1747 code. A multimeter is crucial for testing voltage, continuity, and resistance. A wiring diagram specific to your vehicle is vital for understanding the circuit layout. Finally, an OBD2 scanner can read and clear DTCs.
Fuse Location: The location of the power mirror fuse varies depending on the vehicle's make, model, and year. Consult your vehicle's owner's manual or a wiring diagram to pinpoint the correct fuse. It's typically located in the interior fuse box or under the hood.
Wiring Diagram Importance: A wiring diagram is indispensable for tracing the circuit path, identifying connectors, and finding testing points. Without it, you'll be troubleshooting blindly. Ensure you have the correct diagram for your specific vehicle.
Testing Procedures: Several testing procedures can help you isolate the short. Voltage testing involves measuring voltage at different points in the circuit to see where the unwanted voltage is present. Continuity testing checks for breaks in the circuit. Resistance testing measures the resistance of components to identify shorts or opens.
Mirror Switch Testing: The mirror switch is a prime suspect. Use a multimeter to check for proper voltage and continuity at the switch terminals. Refer to the wiring diagram to identify the correct terminals and testing procedures.
Mirror Motor Testing: Disconnect the mirror motor from the circuit before testing. You can apply voltage directly to the motor to see if it operates. Also, check for shorts in the motor windings using a multimeter. Excessive current draw can indicate a shorted motor.
BCM Involvement: While less common, the BCM can be involved if it controls the power distribution to the mirror circuit. Check the BCM for proper operation and connectivity. This usually involves checking for proper voltage at the BCM connector related to the mirror circuit and verifying the BCM's grounding. BCM diagnosis is typically a last resort.
Related DTCs: Check for other DTCs related to the power mirrors or other body control functions. Diagnose and address any related codes before focusing solely on the B1747 code, as they may point to a more fundamental issue.
Potential Risks: Ignoring a short to battery can lead to several risks, including an electrical fire, damage to the BCM, and malfunctioning mirror. Addressing the issue promptly is crucial to prevent further damage and ensure vehicle safety.
Repair Difficulty: The repair difficulty can be moderate, depending on the location and complexity of the short. If the short is easily accessible and the wiring is straightforward, you might be able to handle the repair yourself. However, if the short is hidden deep within the wiring harness or requires specialized tools, consider seeking professional help.
Parts Cost: The cost of replacement parts varies depending on the component needing replacement. A mirror switch is usually relatively inexpensive, while a new mirror motor or wiring harness can be more costly. Research prices for replacement parts before starting the repair to get an idea of the overall cost.
Labor Cost: Labor costs also vary depending on the complexity of the repair and the shop's hourly rate. A simple switch replacement might only take an hour or two, while a more extensive wiring repair could take several hours. Obtain quotes from multiple shops before authorizing any repairs to ensure you're getting a fair price.
Common Mistakes: Several common mistakes can hinder the diagnostic process. Failing to properly diagnose the root cause is a major pitfall. Replacing parts without proper testing can be costly and ineffective. Ignoring related DTCs can lead to overlooking the underlying problem. Always thoroughly diagnose the issue before replacing any parts and use proper testing procedures.
Frequently Asked Questions:
What does the B1747 code mean? It signifies a short to battery condition within the passenger side mirror's horizontal adjustment circuit. This means the circuit is receiving unintended power.
What are the symptoms of a B1747 code? The most common symptom is the passenger side mirror not adjusting horizontally. You might also experience a blown fuse.
Can I fix the B1747 code myself? It depends on your mechanical and electrical skills. If you are comfortable using a multimeter and reading wiring diagrams, you might be able to diagnose and repair the issue yourself.
What tools do I need to diagnose the B1747 code? You'll need a multimeter, a wiring diagram for your vehicle, and an OBD2 scanner.
How do I test the mirror switch? Use a multimeter to check for proper voltage and continuity at the switch terminals. Refer to the wiring diagram for terminal identification.
Where is the power mirror fuse located? Consult your vehicle's owner's manual or wiring diagram to find the fuse location. It is typically in the interior fuse box or under the hood.
Is the BCM likely to be the problem? The BCM is less likely to be the problem, but it's possible. Check the BCM for proper operation and connectivity as a last resort.
What should I do if I'm not comfortable diagnosing the B1747 code myself? Consult a qualified mechanic or automotive electrician for professional diagnosis and repair.
Conclusion:
The B1747 DTC indicates a short to battery within the passenger side mirror's horizontal adjustment circuit. A systematic diagnostic approach using a multimeter, wiring diagram, and careful testing procedures is crucial for identifying and resolving the root cause. Addressing this issue promptly will restore full mirror functionality and prevent potential damage to other vehicle systems.