Introduction
The B1986 diagnostic trouble code (DTC) indicates a fault within the driver's seat seatback auto-glide rearward switch circuit. This circuit is integral to the proper functioning of power seats, allowing for convenient adjustment of the seatback position. A failure in this circuit can prevent the seatback from automatically gliding rearward, impacting comfort and potentially safety. Addressing this issue promptly is crucial for restoring full seat functionality and ensuring a comfortable driving experience.
Comprehensive Table: B1986 Driver's Seat Seatback Auto glides Rearward Switch Circuit Failure
| Topic | Description | Potential Causes |
|---|---|---|
| B1986 DTC Definition | Indicates a malfunction in the electrical circuit responsible for the driver's seatback's automatic rearward gliding function. The vehicle's computer (usually the Body Control Module or Seat Control Module) has detected an open circuit, short to ground, or short to voltage within this switch circuit. This circuit includes the switch itself, wiring harness, connectors, and potentially other related components. | Faulty Auto-Glide Rearward Switch, Damaged Wiring, Corroded Connectors, Open Circuit, Short Circuit (to ground or voltage), Faulty Seat Control Module (SCM) |
| Auto-Glide Functionality | The auto-glide feature, when functioning correctly, allows the driver's seatback to automatically move rearward when the seat is moved to its rearmost position. This creates additional space for entry and exit, particularly useful for larger individuals or in vehicles with limited rear seat access. The system typically relies on a combination of mechanical linkages, electric motors, and electronic sensors to determine seat position and activate the auto-glide function. The switch in question signals the SCM when the seat is approaching its rearmost position, prompting the rearward movement. | Mechanical Binding, Faulty Seat Track Position Sensor, Inadequate Power Supply to Seat Motor |
| Switch Circuit Components | The B1986 circuit primarily comprises the auto-glide rearward switch itself, the wiring harness connecting the switch to the Seat Control Module (SCM) or Body Control Module (BCM), and the connectors that join these components. The switch is typically a momentary switch, meaning it only activates when pressed. The wiring harness consists of multiple wires responsible for carrying power, ground, and signal information between the switch and the control module. Connectors provide secure electrical connections between the wires and the components. | Damaged Switch Contacts, Broken Wires, Loose Connectors, Corroded Terminals |
| Diagnostic Procedures | To diagnose a B1986 DTC, a systematic approach is required. This typically begins with visually inspecting the switch, wiring harness, and connectors for any signs of damage, corrosion, or loose connections. A multimeter can then be used to test the switch for continuity and proper function. The wiring harness can be checked for open circuits, short circuits, and proper voltage levels. A scan tool can be used to monitor the switch signal and verify that it is being received by the SCM or BCM. Finally, the SCM or BCM itself may need to be tested or replaced if all other components check out. | Incorrect Diagnostic Tools, Lack of Technical Information, Improper Testing Procedures |
| Possible Symptoms | The most common symptom of a B1986 DTC is the failure of the driver's seatback to automatically glide rearward when the seat is moved to its rearmost position. Other potential symptoms may include intermittent seatback movement, erratic seatback behavior, or the inability to adjust the seatback at all. In some cases, other power seat functions may also be affected. | No Auto-Glide Function, Intermittent Seat Movement, Complete Seatback Inoperability, Other Power Seat Issues |
| Potential Repair Solutions | Repairing a B1986 DTC typically involves addressing the underlying cause of the circuit failure. This may involve replacing the faulty auto-glide rearward switch, repairing or replacing damaged wiring, cleaning or replacing corroded connectors, or replacing the SCM or BCM. In some cases, simply cleaning and re-seating the connectors may be sufficient to resolve the issue. After any repairs are made, it is important to clear the DTC and verify that the seatback auto-glide function is working correctly. | Switch Replacement, Wiring Repair/Replacement, Connector Cleaning/Replacement, Seat Control Module Replacement |
| Tools & Equipment Needed | Diagnosing and repairing a B1986 DTC typically requires a variety of tools and equipment, including a multimeter, scan tool, wiring diagram, wire strippers, crimpers, soldering iron, and various hand tools. A multimeter is essential for testing the switch, wiring harness, and connectors for continuity, voltage, and resistance. A scan tool is needed to read and clear DTCs and monitor the switch signal. Wiring diagrams provide valuable information about the circuit layout and component locations. | Multimeter, Scan Tool, Wiring Diagram, Wire Strippers, Crimpers, Soldering Iron, Hand Tools |
| Related Diagnostic Codes | Several other DTCs may be related to a B1986 DTC, particularly those related to other power seat functions or the SCM/BCM. These codes may provide additional clues about the underlying cause of the problem. For example, codes related to the seat motor, seat position sensors, or other switches in the power seat system may indicate a common issue affecting multiple components. | Other Power Seat DTCs, SCM/BCM Communication Errors, Seat Motor DTCs, Seat Position Sensor DTCs |
| Safety Precautions | When working on electrical systems, it is important to take appropriate safety precautions. This includes disconnecting the negative battery cable before beginning any work, using insulated tools, and avoiding contact with exposed wires. If working on the seat while it is still installed in the vehicle, be careful not to damage any other components. When soldering, wear appropriate eye protection and work in a well-ventilated area. | Disconnect Battery, Insulated Tools, Eye Protection, Proper Ventilation |
Detailed Explanations
B1986 DTC Definition: This code pinpoints an electrical issue specifically within the circuit that controls the automatic rearward movement of the driver's seatback. The vehicle's computer monitors this circuit, and when it detects an abnormal condition, like a break in the wiring or a short circuit, it triggers the B1986 code. This signals that the seatback auto-glide function isn't operating as intended.
Auto-Glide Functionality: The auto-glide feature is designed to enhance convenience, particularly for drivers who need extra space when entering or exiting the vehicle. When the seat is moved to its rearmost position, the system automatically moves the seatback further back, creating more room. This system relies on electronic signals and mechanical components working in harmony.
Switch Circuit Components: The circuit responsible for the auto-glide function consists of several key elements. The auto-glide rearward switch is the primary input device, signaling the system when the rearward movement should occur. The wiring harness provides the electrical pathways connecting the switch to the control module, and connectors ensure secure and reliable connections between the components.
Diagnostic Procedures: A systematic approach is vital for accurately diagnosing the cause of the B1986 DTC. Begin with a thorough visual inspection of all components, looking for any signs of damage or corrosion. Use a multimeter to test the switch and wiring for continuity and proper voltage. A scan tool can provide valuable data about the switch signal and the overall system operation.
Possible Symptoms: The most obvious symptom is the failure of the seatback to automatically glide rearward. However, other issues may arise, such as intermittent or erratic seatback movement, or even the complete inability to adjust the seatback. These symptoms can help narrow down the potential causes of the problem.
Potential Repair Solutions: Addressing a B1986 DTC involves targeting the root cause of the circuit failure. This may require replacing a faulty switch, repairing or replacing damaged wiring, cleaning or replacing corroded connectors, or even replacing the SCM or BCM. It's crucial to thoroughly test the system after any repairs to ensure the problem is resolved.
Tools & Equipment Needed: Proper diagnosis and repair require specific tools. A multimeter is essential for electrical testing, while a scan tool allows you to read and clear DTCs and monitor system parameters. Wiring diagrams are invaluable for understanding the circuit layout. Other tools like wire strippers, crimpers, and a soldering iron may be necessary for wiring repairs.
Related Diagnostic Codes: Be aware of other DTCs that may be related to the B1986 code. Codes related to other power seat functions, the SCM/BCM, or seat motor can provide additional clues about the underlying problem and help you diagnose the issue more effectively.
Safety Precautions: Prioritize safety when working on electrical systems. Always disconnect the negative battery cable to prevent electrical shock. Use insulated tools to avoid short circuits. Wear eye protection when soldering. These precautions will help you stay safe while working on the vehicle.
Frequently Asked Questions
What does the B1986 code mean? It indicates a fault in the driver's seat seatback auto-glide rearward switch circuit. This means the system that automatically moves the seatback rearward when the seat is moved back is malfunctioning.
What is the most common cause of the B1986 code? A faulty auto-glide rearward switch is a frequent culprit. This switch may be damaged, worn, or have corroded contacts.
Can I fix the B1986 code myself? It depends on your mechanical and electrical skills. If you're comfortable using a multimeter and scan tool, you may be able to diagnose and repair the issue yourself. However, if you're not experienced, it's best to consult a qualified mechanic.
How much does it cost to fix a B1986 code? The cost varies depending on the cause of the problem and the labor rates in your area. Replacing a faulty switch is typically less expensive than replacing the SCM or BCM.
Will the B1986 code affect my car's performance? The B1986 code primarily affects the comfort and convenience of the driver's seat. It typically does not affect the car's overall performance or safety. However, it can be a nuisance and may indicate a more serious electrical problem.
Conclusion
The B1986 Driver's Seat Seatback Auto glides Rearward Switch Circuit Failure indicates a specific issue within the vehicle's power seat system. By following a systematic diagnostic approach and addressing the underlying cause of the circuit failure, you can restore the seatback auto-glide function and ensure a comfortable driving experience; always prioritize safety and consult a professional if you are unsure about any aspect of the repair.