B1720 — Seat Driver Forward Switch Circuit Short To Ground #

This code description may vary depending on the vehicle manufacturer. Below is a list of known label variations for B1720:

• Seat Driver Forward Switch Circuit Short To Ground (Generic/OEMs)
• Front Seat Driver Forward Position Switch Circuit Low (Ford, Lincoln, Mercury)
• Driver Seat Slide Motor Switch Shorted to Ground (Toyota, Lexus)
• Seat Adjuster Forward Switch Circuit Short to Ground (GM, Chevrolet, GMC)

Summary of Code B1720 #

B1720 is a diagnostic trouble code (DTC) that signals an electrical fault in the driver seat forward movement switch circuit. Specifically, it indicates that the control module has detected a short to ground in the wiring or switch that allows the driver’s seat to slide forward. This code is most commonly triggered when the seat cannot be moved forward, or the seat switch behaves erratically. The affected system is part of the vehicle’s comfort and convenience features, and while not immediately safety-critical, it can impact driving ergonomics. Addressing this issue promptly ensures ongoing comfort and can prevent further electrical complications.

Frequent Symptoms for Code B1720 #

When this code appears, the most noticeable symptoms are related to the inability to adjust the driver’s seat forward. Other electrical quirks might also be present. Here are the most common symptoms:

• Driver’s seat does not move forward when using the switch
• Unusual clicking or buzzing sounds from the seat area
• Seat moves only in certain directions (back, up/down, but not forward)
• Intermittent function of seat adjustment controls
• Possible illumination of the airbag or seat warning light (in some models)
• Blown fuse in the seat circuit

Most Likely Causes for Code B1720 #

The B1720 code is most often linked to wiring or switch malfunctions. Here are the most probable causes, listed in order of frequency:

1. Shorted wiring harness for the seat forward switch (damaged, pinched, or frayed wires touching metal/chassis)
2. Faulty seat forward switch (internal short to ground)
3. Corroded or loose electrical connectors at the seat switch or seat motor
4. Seat motor internal short (less common)
5. Faulty control module (rare, but possible if all else checks out)

Step-by-Step Diagnosis for Code B1720 #

Proper diagnosis is essential to pinpoint the root cause before replacing any parts. Follow these steps in sequence:

1. Verify the code using a scan tool and check for additional seat-related DTCs.
2. Inspect the seat forward switch wiring harness visually for obvious damage, pinching, or signs of abrasion.
3. Disconnect the seat forward switch and inspect the electrical connector for corrosion or bent pins.
4. Test the seat forward switch for continuity using a multimeter; check for short to ground.
5. Check the seat motor wiring and connector, ensuring no wires are shorted to ground or chassis.
6. Test the seat motor separately, if accessible, to rule out an internal short.
7. Clear the code and retest after each repair or adjustment to see if the fault returns.

Possible Repairs for Code B1720 #

The necessary repair will depend on the diagnostic findings. Here are the most common fixes:

• Repair or replace damaged seat switch wiring (most frequent solution)
• Replace the driver seat forward switch if found defective
• Clean or replace corroded connectors at the switch or seat motor
• Repair or replace the seat motor if it is internally shorted
• Replace the seat control module (only after all other options are ruled out)

Is It Safe to Drive with Code B1720? #

Yes, you can usually continue to drive with code B1720 present, as this fault does not directly affect core vehicle safety systems. However, the inability to adjust the driver’s seat can limit comfort and, in extreme cases, safe operation if the seat cannot be positioned correctly for the driver. It is best to address the issue at your earliest convenience, especially if more than one seat function is affected.

Vehicles Most Commonly Affected by Code B1720 #

While B1720 can appear in a wide range of vehicles equipped with power-adjustable driver’s seats, it is most commonly reported in models from:

• Ford (F-150, Explorer, Fusion, Mustang)
• Chevrolet / GMC (Silverado, Tahoe, Acadia)
• Toyota / Lexus (Camry, Avalon, ES series)
• Honda / Acura (Accord, MDX)
• Nissan / Infiniti (Altima, Maxima, QX series)

Common Mistakes & Best Practices for Code B1720 #

Avoiding common pitfalls can save time and money when addressing B1720. Here’s what to watch for:

• Avoid replacing the seat switch or motor without checking the wiring first. Harness damage is the most frequent cause.
• Don’t overlook connector corrosion, especially in older vehicles or those exposed to moisture.
• Always clear the code and retest after each step to confirm the repair.
• Use the correct wiring diagrams for your exact model and year.
• If unsure, consult an OEM service manual or a qualified professional before attempting repairs.

Quick FAQ for Code B1720 #

Here are answers to common questions about this DTC:

• Q: Can I manually adjust the seat if the switch fails?
  A: In most cases, no. Power seats rely on electrical controls and motors. Manual override is rare and usually not possible without tools.
• Q: Will this code affect the passenger seat or other seat functions?
  A: B1720 specifically refers to the driver’s seat forward switch. Other seat functions and passenger seat controls are typically independent, but shared wiring faults could potentially affect multiple functions.