B1979 – Passenger Seat Rearward Switch Circuit Short to Battery

The ODBII code B1979 indicates a malfunction in the passenger seat rearward switch circuit, specifically a short circuit to the battery, which means there is an unintended connection causing the circuit to receive constant power.

The severity of ODBII code B1979 is moderate.

Common Causes For: B1978 Passenger’s Front Seat Down Switch Circuit Short to Battery

• Shorted wiring or connectors
• Faulty passenger seat rearward switch
• Damaged seat control module
• Corroded or damaged terminals
• Grounding issues
• Faulty power supply to the switch

Common misdiagnosis for B1979 Passenger Seat Rearward Switch Circuit Short to Battery

• Faulty passenger seat switch
• Wiring harness issues
• Short circuit in the seat control module
• Malfunctioning body control module (BCM)
• Defective seat position sensor
• Grounding issues
• Battery or power supply problems

Common Troubleshooting Steps

When dealing with an OBD-II code B1979, which indicates a “Passenger Seat Rearward Switch Circuit Short to Battery,” there are several common troubleshooting steps you can follow to diagnose and potentially resolve the issue. Here’s a structured approach:

• Check the Vehicle’s Manual: Refer to the vehicle’s service manual for specific information regarding the passenger seat switch circuit and wiring diagrams.
• Visual Inspection: **Wiring and Connectors: Inspect the wiring harness and connectors associated with the passenger seat switch. Look for any signs of damage, fraying, or corrosion.
• **Switch Condition: Check the passenger seat rearward switch for any physical damage or signs of wear.
• Test the Switch: **Continuity Test: Use a multimeter to check for continuity in the switch. Disconnect the switch and test the terminals to ensure it operates correctly.
• **Functionality: If possible, test the switch by applying power directly to it to see if it functions as intended.
• Check for Short Circuits: **Wiring Inspection: Look for any shorts in the wiring that could be causing the circuit to be shorted to battery voltage. This may involve checking for pinched wires or damaged insulation.
• **Ground Connections: Ensure that all ground connections are secure and free of corrosion.
• Scan for Additional Codes: Use an OBD-II scanner to check for any additional trouble codes that may provide more context or indicate related issues.
• Inspect the Seat Module: If the vehicle has a seat control module, inspect it for faults. This may involve checking for software updates or known issues with the module.
• Check Fuses and Relays: Inspect the fuses and relays associated with the seat control system. A blown fuse may indicate an overload or short circuit.
• Perform a Reset: After addressing any issues found, clear the trouble codes using an OBD-II scanner and take the vehicle for a test drive to see if the code returns.
• Consult a Professional: If the issue persists after performing these steps, it may be necessary to consult a professional mechanic or an automotive electrician for further diagnosis.
• Document Findings: Keep a record of any tests performed, findings, and repairs made. This documentation can be helpful for future reference or if professional assistance is needed. By following these steps, you should be able to identify and resolve the issue related to the B1979 code. Always ensure safety precautions are taken when working on electrical systems in vehicles.