Introduction
The B1720 diagnostic trouble code (DTC) indicates a fault within the driver's seat forward switch circuit, specifically a short to ground. This means the electrical circuit responsible for moving the driver's seat forward has unintentionally connected to ground, causing an electrical malfunction. This issue can prevent the seat from moving forward, impacting driver comfort and potentially safety. Understanding the causes, symptoms, and troubleshooting steps for this code is crucial for resolving the problem efficiently.
Table: B1720 Seat Driver Forward Switch Circuit Short To Ground
| Topic | Description | Common Causes |
|---|---|---|
| Definition of B1720 | A diagnostic trouble code (DTC) indicating a short circuit to ground within the driver's seat forward switch circuit. This prevents the seat from moving forward electrically. | Damaged Wiring: Frayed, cracked, or rodent-chewed wires within the seat wiring harness. Faulty Switch: The driver's seat forward switch itself is internally shorted. Short to Ground: A wire in the circuit is physically contacting the vehicle's chassis or another ground point. Water Intrusion: Corrosion caused by water damage in connectors or wiring. Loose Connections: Corroded or loose connectors in the seat circuit. |
| Symptoms | The driver's seat will not move forward when the forward switch is activated. Other seat functions (backward, up/down, lumbar support) may or may not be affected. The seat motor may make a clicking sound, or there may be no response at all. The vehicle's body control module (BCM) or seat control module may store the B1720 DTC. Intermittent seat movement. | No seat movement forward. Intermittent forward seat movement. Other seat functions may be affected. Clicking sound from seat motor. B1720 DTC present. |
| Affected Components | Driver's seat forward switch, seat motor, wiring harness connecting the switch and motor, seat control module (if equipped), body control module (BCM). | Driver's seat forward switch. Seat motor. Wiring harness. Seat control module (if equipped). Body control module (BCM). |
| Diagnostic Tools | Multimeter, scan tool (OBD-II scanner), wiring diagram for the specific vehicle make and model, test light, circuit tester, visual inspection tools (flashlight, magnifying glass). | Multimeter. Scan tool (OBD-II scanner). Wiring diagram. Test light. Circuit tester. |
| Troubleshooting Steps | Visual Inspection: Check wiring and connectors for damage. Switch Testing: Test the forward switch for continuity and proper function. Wiring Continuity Test: Check for shorts to ground using a multimeter. Voltage Test: Verify voltage at the switch and motor. Component Isolation: Disconnect components to isolate the short. Module Testing: If applicable, test the seat control module. | Visual inspection of wiring and connectors. Testing the forward switch. Wiring continuity test. Voltage test. Component isolation. Module testing (if applicable). |
| Repair Procedures | Repair or replace damaged wiring. Replace the faulty driver's seat forward switch. Clean corroded connectors. Secure loose connections. Replace the seat motor (if the motor is determined to be the cause of the short). Replace the seat control module (if faulty). | Repair or replace damaged wiring. Replace the forward switch. Clean corroded connectors. Secure loose connections. Replace the seat motor. Replace the seat control module (if faulty). |
| Preventative Measures | Regularly inspect seat wiring for damage. Avoid spilling liquids near the seat. Address any seat movement issues promptly. Keep the interior of the vehicle clean and dry. | Regular inspection of seat wiring. Avoid spilling liquids. Address seat movement issues promptly. Keep the interior clean and dry. |
| Related DTCs | Other seat-related DTCs, such as those related to the seat motor, seat position sensors, or other switch circuits. | Other seat-related DTCs. |
Detailed Explanations
Definition of B1720: The B1720 code is a specific diagnostic trouble code that your vehicle's computer (usually the Body Control Module or Seat Control Module) sets when it detects an electrical short circuit to ground in the circuit controlling the driver's seat forward movement. This short means that electricity is flowing to ground instead of through the intended circuit components. The result is the seat's inability to move forward using the electric motor.
Symptoms: The most obvious symptom is the driver's seat not moving forward when the forward switch is pressed. Other symptoms may include intermittent forward movement, a clicking sound from the seat motor when the switch is activated, and potentially, other seat functions being affected. The presence of the B1720 DTC, retrievable with an OBD-II scanner, confirms the specific fault.
Affected Components: The B1720 code implicates several components within the driver's seat system. The driver's seat forward switch is the primary suspect, as it directly controls the forward movement. The seat motor, responsible for physically moving the seat, is also a potential culprit. The wiring harness connecting these components is crucial, as damage to the wiring can create a short to ground. If equipped, the seat control module manages the seat's functions and can be affected. Finally, the body control module (BCM) may be involved in monitoring and reporting the fault.
Diagnostic Tools: Diagnosing the B1720 code requires several tools. A multimeter is essential for testing voltage, continuity, and resistance in the circuit. A scan tool (OBD-II scanner) is needed to retrieve the B1720 DTC and any other related codes. A wiring diagram specific to your vehicle's make and model is crucial for understanding the circuit layout. A test light or circuit tester can help identify the presence of voltage in the circuit. Finally, visual inspection tools like a flashlight and magnifying glass are helpful for examining wiring and connectors for damage.
Troubleshooting Steps: A systematic approach is necessary to diagnose the B1720 code. First, perform a visual inspection of the wiring and connectors for any signs of damage, corrosion, or loose connections. Next, test the forward switch for continuity and proper function using a multimeter. A wiring continuity test using a multimeter can identify shorts to ground in the wiring. A voltage test can verify that the switch and motor are receiving the correct voltage. Component isolation, by disconnecting components one at a time, can help pinpoint the location of the short. If applicable, module testing of the seat control module may be necessary.
Repair Procedures: Repairing the B1720 code involves addressing the identified fault. Repairing or replacing damaged wiring is crucial to eliminate the short to ground. Replacing the faulty driver's seat forward switch is necessary if the switch is determined to be the cause. Cleaning corroded connectors and securing loose connections can restore proper electrical contact. Replacing the seat motor may be required if the motor itself is shorted. In rare cases, replacing the seat control module may be necessary if it is faulty.
Preventative Measures: Preventing the B1720 code involves proactive maintenance. Regularly inspect seat wiring for any signs of damage. Avoid spilling liquids near the seat, as this can cause corrosion. Address any seat movement issues promptly to prevent further damage. Keep the interior of the vehicle clean and dry to minimize the risk of corrosion.
Related DTCs: The B1720 code may be accompanied by other seat-related DTCs, such as those related to the seat motor, seat position sensors, or other switch circuits. These related codes can provide further clues to the underlying problem. Addressing all related DTCs is crucial for a complete and effective repair.
Frequently Asked Questions
What does the B1720 code mean?
The B1720 code indicates a short to ground in the driver's seat forward switch circuit, preventing the seat from moving forward. This means the circuit is unintentionally connected to the vehicle's ground.
Can I fix the B1720 code myself?
Depending on your mechanical skills, you might be able to diagnose and repair the issue. However, electrical troubleshooting requires caution and knowledge of vehicle wiring.
What tools do I need to diagnose the B1720 code?
You'll need a multimeter, scan tool (OBD-II scanner), wiring diagram, test light, and basic hand tools. A wiring diagram specific to your vehicle is essential.
How do I test the seat forward switch?
Use a multimeter to check for continuity when the switch is activated. Refer to the wiring diagram for the specific terminals to test.
Is it safe to drive with the B1720 code?
While not immediately dangerous, a malfunctioning seat can be uncomfortable and potentially unsafe. Address the issue as soon as possible.
How much does it cost to fix the B1720 code?
The cost varies depending on the cause and repair needed. Replacing a switch is generally less expensive than repairing damaged wiring or replacing a module.
Conclusion
The B1720 code signifies a short to ground in the driver's seat forward switch circuit, preventing the seat from moving forward. A systematic approach to diagnosis and repair, including visual inspection, component testing, and wiring analysis, is essential for resolving this issue. Regularly inspecting and maintaining seat wiring can help prevent future occurrences.