Introduction:
The B1708 diagnostic trouble code (DTC) indicates a problem within the driver's seat recline rearward switch circuit. Specifically, the circuit is experiencing a short to ground. Understanding the causes and troubleshooting steps for this code is crucial for restoring proper seat functionality and avoiding potential electrical issues. This article provides a comprehensive guide to diagnosing and resolving the B1708 DTC.
Comprehensive Guide to B1708
| Topic | Description | Possible Causes |
|---|---|---|
| B1708 Definition | The B1708 DTC signifies that the vehicle's computer (typically the Body Control Module or Seat Control Module) has detected an unintended electrical connection between the driver's seat recline rearward switch circuit and the vehicle's ground. This is often referred to as a "short to ground." | Damaged wiring, faulty switch, internal short in the seat motor, corroded connectors, chafed insulation. |
| Symptoms | The most common symptom is a non-functional driver's seat recline feature (specifically the rearward motion). Other symptoms may include intermittent recline operation, the inability to adjust other seat functions (if interconnected), and in rare cases, potential electrical issues like blown fuses or battery drain (though less likely with a simple switch circuit). | Seat does not recline backward, intermittent recline function, other seat functions affected, blown fuses (rare), possible battery drain (uncommon). |
| Affected Components | The primary components involved are the driver's seat recline rearward switch, the wiring harness connecting the switch to the seat control module (or Body Control Module), the seat control module itself, and the seat recline motor. The ground connection for the circuit is also a critical component. | Driver's seat recline rearward switch, wiring harness, seat control module/Body Control Module, seat recline motor, ground connection. |
| Diagnostic Tools | A multimeter is essential for testing voltage, continuity, and resistance. A scan tool capable of reading and clearing DTCs is necessary. A wiring diagram specific to the vehicle make, model, and year is invaluable. A test light can also be useful for quickly checking for power and ground. | Multimeter, scan tool, wiring diagram, test light. |
| Troubleshooting Steps | 1. Verify the DTC: Confirm the presence of the B1708 code using a scan tool. 2. Inspect Wiring and Connectors: Visually inspect the wiring harness and connectors associated with the driver's seat recline switch, looking for signs of damage, corrosion, or chafing. 3. Test the Switch: Use a multimeter to test the recline switch for proper operation. 4. Isolate the Short: Disconnect components one at a time to isolate the short to ground. 5. Check the Motor: Test the seat recline motor for proper operation. 6. Inspect Ground Connections: Ensure the ground connections for the seat are clean and secure. 7. Consult Wiring Diagram: Refer to the wiring diagram to trace the circuit and identify potential short locations. | Damaged wiring, faulty switch, shorted motor, corroded ground connections. |
| Common Mistakes | Failing to properly inspect the wiring harness, assuming the switch is faulty without testing, neglecting to check ground connections, and not using a wiring diagram are common mistakes. Replacing the seat control module without properly diagnosing the problem is also a frequent, and often costly, error. | Skipping wiring inspection, assuming faulty switch, neglecting ground checks, not using wiring diagram, premature control module replacement. |
| Repair Procedures | Repair procedures depend on the identified cause. Damaged wiring may require splicing or replacement. Corroded connectors should be cleaned or replaced. A faulty switch needs replacement. A shorted motor also needs replacement. Secure or clean ground connections. After repairs, clear the DTC and retest the system. | Wire splicing/replacement, connector cleaning/replacement, switch replacement, motor replacement, ground connection cleaning/securing. |
| Related DTCs | Other DTCs related to seat functionality or electrical issues may be present alongside B1708. These might include codes related to other seat motors (forward/backward, up/down), seat heaters, or general electrical system problems. Addressing these related codes can provide additional clues to the root cause of the B1708 code. | Codes related to other seat motors, seat heaters, general electrical system issues. |
| Safety Precautions | Always disconnect the negative battery cable before working on any electrical components. Be careful when working around the seat frame and moving parts to avoid injury. Consult the vehicle's repair manual for specific safety recommendations. | Disconnect battery, be careful around seat frame, consult repair manual. |
Detailed Explanations
B1708 Definition:
The B1708 diagnostic trouble code (DTC) indicates a short to ground in the driver's seat recline rearward switch circuit. This means that the electrical circuit intended to control the rearward recline function of the driver's seat has an unintended connection to the vehicle's chassis, creating a path for electricity to flow directly to ground instead of through the intended components. This short circuit disrupts the normal operation of the seat recline function.
Symptoms:
The primary symptom associated with the B1708 code is the failure of the driver's seat to recline backward. The seat may remain fixed in its current position or exhibit intermittent recline function. In some cases, if other seat functions are controlled by the same module, they may also be affected. Blown fuses or a battery drain are less common but possible, especially if the short is severe.
Affected Components:
The components directly involved in the B1708 code include the driver's seat recline rearward switch itself, the wiring harness that connects the switch to the seat control module (or Body Control Module), the seat control module (or Body Control Module) which processes the switch signal and controls the seat motor, the seat recline motor responsible for moving the seat back, and the ground connection that provides the electrical reference point for the circuit.
Diagnostic Tools:
A multimeter is crucial for testing voltage, continuity, and resistance within the circuit. A scan tool is necessary to read and clear the B1708 DTC and any other related codes. A wiring diagram specific to the vehicle make, model, and year is essential for tracing the circuit and identifying potential short locations. A test light can be used to quickly check for power and ground at various points in the circuit.
Troubleshooting Steps:
- Verify the DTC: Use a scan tool to confirm the presence of the B1708 code and any other related codes.
- Inspect Wiring and Connectors: Carefully examine the wiring harness and connectors associated with the driver's seat recline switch. Look for any signs of damage, such as cuts, abrasions, or melted insulation. Also, check for corrosion or loose connections.
- Test the Switch: Use a multimeter to test the recline switch for proper operation. Check for continuity between the switch terminals in both the "on" and "off" positions. Refer to the wiring diagram for the correct terminal identification.
- Isolate the Short: Disconnect components one at a time to isolate the short to ground. Start by disconnecting the seat recline motor. If the code clears, the motor is likely the source of the short. If the code remains, disconnect the switch. If the code clears, the switch is likely the source. If the code persists, the short is likely in the wiring harness.
- Check the Motor: Test the seat recline motor for proper operation. Apply power and ground directly to the motor terminals to see if it functions correctly. If the motor does not operate or exhibits unusual behavior, it may be faulty.
- Inspect Ground Connections: Ensure that the ground connections for the seat are clean and secure. A poor ground connection can cause electrical problems and may contribute to the B1708 code.
- Consult Wiring Diagram: Refer to the wiring diagram to trace the circuit and identify potential short locations. The wiring diagram will show the location of all the components in the circuit and the wiring connections between them.
Common Mistakes:
One common mistake is failing to thoroughly inspect the wiring harness for damage. Another is assuming the switch is faulty without properly testing it. Neglecting to check the ground connections is also a frequent oversight. Replacing the seat control module without properly diagnosing the problem is another common, and often unnecessary, expense. Always use a wiring diagram to guide your troubleshooting.
Repair Procedures:
The repair procedure will depend on the identified cause of the B1708 code. Damaged wiring may require splicing or replacement. Corroded connectors should be cleaned or replaced. A faulty switch needs replacement. A shorted motor also needs replacement. Ensure that all ground connections are clean and secure. After completing the repairs, clear the DTC and retest the system to ensure that the problem has been resolved.
Related DTCs:
Other DTCs related to seat functionality or electrical issues may be present alongside the B1708 code. These may include codes related to other seat motors (forward/backward, up/down), seat heaters, or general electrical system problems. Addressing these related codes can provide additional clues to the root cause of the B1708 code. For example, a code related to a short in the seat heater circuit could indicate a damaged wiring harness that is also affecting the recline switch circuit.
Safety Precautions:
Always disconnect the negative battery cable before working on any electrical components. This will prevent accidental electrical shock and damage to the vehicle's electrical system. Be careful when working around the seat frame and moving parts to avoid injury. Consult the vehicle's repair manual for specific safety recommendations.
Frequently Asked Questions
What does the B1708 code mean?
The B1708 code indicates a short to ground in the driver's seat recline rearward switch circuit. This means there's an unintended electrical connection to the vehicle's chassis.
What are the symptoms of a B1708 code?
The most common symptom is the driver's seat not reclining backward. Other symptoms may include intermittent recline function or other seat functions being affected.
What causes the B1708 code?
Possible causes include damaged wiring, a faulty switch, a shorted motor, or corroded ground connections. A wiring diagram is very helpful to find the root cause.
How do I fix the B1708 code?
Fixing the B1708 code involves diagnosing the cause and repairing the affected component. This may include repairing or replacing wiring, the switch, or the motor.
Can I drive with a B1708 code?
While you can drive with a B1708 code, it's not recommended. The seat recline function will likely be impaired, and there's a potential for further electrical problems.
Conclusion
The B1708 DTC, indicating a short to ground in the driver's seat recline rearward switch circuit, requires careful diagnosis and repair. By following the troubleshooting steps outlined in this article and using the appropriate diagnostic tools, you can effectively identify and resolve the issue, restoring proper seat functionality. Always prioritize safety by disconnecting the battery before working on electrical components and consulting the vehicle's repair manual.