B1720 — Seat Driver Forward Switch Circuit Short To Ground

body electrical

Is it safe to drive?

Short-term driving is OK Usually safe to drive — body codes rarely affect drivability. Exceptions: exterior lighting and wipers in bad weather, and central locking faults that can leave the car unsecured.

How to diagnose with an OBD scanner

Read the code and freeze frame Connect an OBD2 scanner, confirm B1720 is stored, and save the freeze frame data — it shows engine conditions when the fault was detected.
Check for companion codes and TSBs Related codes often reveal the real root cause. Also check manufacturer technical service bulletins (TSB) for your make and model — many B0xxx issues have factory fixes or software updates. Search by VIN on the manufacturer site or nhtsa.gov.
Inspect wiring and connectors Visually inspect the wiring harness and connectors related to the body electrical system for damage, corrosion, chafing or poor contact.
Subsystem check Operate the affected function while watching its switch and motor PIDs in live data.
Subsystem check Inspect connectors and wiring at flex points (door jambs, tailgate hinges) — wires break there first.
Verify the repair Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm B1720 does not return.

Approximate repair cost

Repair cost depends on which component actually failed. Typical scenarios for B1720 (parts and labor, USD, independent shop rates): BCM repair or replacement: $300–$900; Repair wiring or connectors: $80–$250; Replace the switch or actuator: $120–$450. Overall, fixing B1720 usually costs between $80 and $900. An accurate diagnosis before buying parts saves money — the most expensive scenario is rarely the first one to check.

Common questions

Is it safe to drive with B1720?

Usually safe to drive — body codes rarely affect drivability. Exceptions: exterior lighting and wipers in bad weather, and central locking faults that can leave the car unsecured.

What does OBD2 code B1720 mean?

Seat Driver Forward Switch Circuit Short To Ground (B1720): a body electrical fault affecting the body electrical system. The car is usually drivable while you plan the repair. Most often caused by damaged wiring in door jambs or wet areas, corroded or loose connectors, faulty switch, motor or actuator of the affected system.

How do I diagnose B1720 myself?

Start with a scan: confirm B1720, save the freeze frame and note any companion codes. Then inspect the wiring and connectors related to the body electrical system, and verify the suspect component against live data before buying parts.

Will B1720 clear itself?

Sometimes B1720 clears after a few drive cycles if the fault was intermittent — for example a loose connector or a tank of bad fuel. The underlying cause usually remains, so the code tends to return. Clear it once; if it comes back, diagnose rather than erase it repeatedly.

How much does it cost to fix B1720?

BCM repair or replacement — $300–$900; Repair wiring or connectors — $80–$250; Replace the switch or actuator — $120–$450. Exact cost depends on the root cause, your vehicle and local labor rates — a proper diagnosis is the cheapest first step.

When your scan tool retrieves trouble code B1720, it's alerting you to an electrical issue within the vehicle's body control system. Specifically, the module has detected that the driver seat forward switch circuit is shorted to ground. This falls under the body electrical category of OBD2 codes, which govern comfort and convenience features rather than engine management.

The seat forward switch plays a straightforward role: it tells the body control module when you've pressed the forward adjustment button on your driver's seat. When you push that button, the circuit should send a specific voltage signal to the BCM. A short to ground means current is taking an unintended path directly to the vehicle frame, bypassing the proper signal. The module won't set B1720 from a single glitch—it watches for the condition to repeat under specific operating parameters before lighting the check engine or warning light. The freeze frame data stored alongside B1720 records engine load, RPM, coolant temperature, and vehicle speed at the moment the fault occurred, giving you precise conditions to replicate during testing.

Common Symptoms of B1720

The seat adjustment function operates intermittently or fails completely when this fault is active. In most vehicles, the seat still moves via other switches or manual controls, but the forward adjustment button becomes unresponsive. The dashboard warning light illuminates to alert you that a body system fault has been detected. You may also notice related body electrical functions behaving erratically if the underlying issue involves wiring shared with other systems. Engine performance remains unaffected—this code touches only comfort features, so acceleration and drivability stay normal. The malfunction indicator may flash briefly before settling to a steady glow, depending on your vehicle's programming.

Most Likely Causes

Corroded or loose electrical connectors rank as the primary culprit behind B1720. Moisture, road salt, and age cause terminal corrosion that creates high resistance, triggering false short-to-ground readings. Wiring damage in door jambs and areas exposed to wet conditions frequently produces this code, as the harness flexes thousands of times as doors open and close. A failed seat adjustment switch itself can internally short circuit and pull the signal to ground. The body control module occasionally fails, though this represents a less common scenario than wiring issues. A blown fuse or failed relay feeding the seat adjustment circuit will also set B1720 when the module detects the abnormal ground path.

Diagnosing B1720

Begin by connecting an OBD2 scanner and confirming B1720 is stored in the module's memory. Record the freeze frame data before clearing anything—this snapshot shows exactly what conditions existed when the fault triggered. Review any additional diagnostic trouble codes present, as related codes often point toward the root cause rather than symptoms. Consult manufacturer technical service bulletins for your specific make, model, and year—many body electrical codes have documented factory fixes or software updates available. Perform a thorough visual inspection of the wiring harness and connectors in the door hinge area and under the seat, looking for chafed insulation, broken strands, corrosion buildup, or loose plugs. Operate the seat forward switch while monitoring its signal voltage in the scanner's live data stream to confirm proper operation. Finally, clear the code, complete a drive cycle that reproduces the freeze frame conditions, and verify B1720 does not return.

Repair Options and Costs

Tackle the cheapest and most probable fixes before considering expensive component replacement. Wiring harness repair or connector replacement typically runs between $80 and $250 for parts and labor at an independent shop. If the switch itself has failed, expect to pay $120 to $450 for replacement including labor. When the body control module requires repair or replacement, costs climb to $300–$900 depending on whether you pursue rebuilding or use OEM new or refurbished units.

Overall, addressing B1720 usually falls between $80 and $900 depending on which component actually failed. The total cost depends entirely on diagnosis results—wiring issues are inexpensive, while BCM replacement commands the higher end. Spending time on accurate diagnosis before purchasing parts almost always saves money compared to randomly replacing expensive components.

Can You Drive with B1720?

Severity level for this code ranks as short—the vehicle remains generally safe to operate. Body electrical codes rarely impact core drivability, engine performance, or safety-critical systems. However, consider the specific function affected. If exterior lighting is involved, night driving becomes hazardous. Wiper motor faults create dangerous visibility during rain or snow. Central locking issues could leave your vehicle unsecured or trapped in an unwanted state. Beyond those specific scenarios, you can continue driving to schedule convenient repair without urgency.