B1727 — Seat Driver Rear Up Switch Circuit Short To Battery

OBD2 code B1727 flags a problem with the body electrical system (seat driver rear up switch circuit short to battery). The car is usually drivable while you plan the repair. Common culprits: corroded or loose connectors, blown fuse or failed relay, faulty switch, motor or actuator of the affected system.

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 B1727 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 B1727 does not return.

Approximate repair cost

Repair cost depends on which component actually failed. Typical scenarios for B1727 (parts and labor, USD, independent shop rates): Repair wiring or connectors: $80–$250; Replace the switch or actuator: $120–$450; BCM repair or replacement: $300–$900. Overall, fixing B1727 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

How do I diagnose B1727 myself?

Start with a scan: confirm B1727, 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 B1727 clear itself?

Sometimes B1727 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.

What are the symptoms of B1727?

Drivers most often notice: no impact on engine operation in most cases, the affected function (locks, windows, lighting, wipers) works intermittently or not at all, warning light on the dashboard.

What does OBD2 code B1727 mean?

How much does it cost to fix B1727?

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

B1727 indicates a fault in the driver's seat rear upward adjustment circuit. Specifically, the code means the body control module has detected an unexpected voltage condition — the switch signal is reading constant battery power when it should only show voltage when pressed. This points to a short circuit somewhere between the switch and the module, or a switch that has failed in a closed position. The seat adjustment system relies on switch inputs to drive small motors that move the seat cushion. When the module sees a stuck-high signal, it cannot properly interpret driver commands and sets B1727.

The module does not log this code after a single glitch. Automotive control units are designed to ignore intermittent electrical noise — the fault must appear repeatedly under similar operating conditions before the system considers it a genuine failure. When the module finally triggers B1727, it records freeze frame data alongside it: engine load, RPM, coolant temperature, and vehicle speed at the moment of detection. That snapshot is your best starting point for recreating the failure during testing.

Common Symptoms of B1727

The driver's rear seat up function does not respond to switch input, or moves only in one direction
The seat adjustment works intermittently — functioning one moment, failing the next
The check engine or body system warning light illuminates on the instrument cluster
No changes to engine performance, fuel economy, or drivability — this fault stays contained within the comfort and convenience system
Adjacent seat functions may also behave erratically if wiring damage affects a shared circuit
The fault code clears temporarily after a battery disconnect, then returns under the original conditions

What Triggers B1727?

Blown fuse or failed relay in the seat adjustment power circuit — the most common and cheapest root cause
Damaged wiring at high-flex points such as door jambs and seat tracks, where repeated motion frays conductors over time
Moisture intrusion in connectors or harness sections running through the vehicle floor, causing corrosion and intermittent short circuits
Faulty adjustment switch internally shorted or worn out, sending phantom signals to the body control module
Failed seat motor or actuator drawing excessive current and pulling the circuit voltage out of specification
Body control module malfunction — the module itself may be misreading valid switch inputs or suffering from internal circuitry damage

How to Diagnose B1727

Connect an OBD2 scanner, confirm B1727 is stored, and record the freeze frame data. Note the engine conditions recorded when the module first flagged the fault.
Pull all related diagnostic trouble codes. Codes in the B1700–B1799 range often share circuits, and a secondary code may point directly to the failed component.
Check manufacturer technical service bulletins for your make and model. Search the NHTSA database or the manufacturer's website using your VIN — many body electrical codes have published fixes or software updates.
Perform a visual inspection of the seat wiring harness, focusing on the connector at the switch and the harness routing along the seat rails. Look for chafed insulation, bent terminals, and corrosion from spilled liquids.
Monitor the switch PID and motor PID in live data while operating the controls. A switch that reads active at all times confirms an internal short; a motor that draws no current suggests an open circuit downstream.
Clear B1727, complete a full drive cycle that replicates the freeze frame conditions, and verify the code does not return. If it comes back, the fault is confirmed and component-level testing is next.

Repair Solutions for B1727

Wiring repair or connector replacement — $80–$250
Seat adjustment switch replacement — $120–$450
Seat motor or actuator replacement — $120–$450
Body control module repair or replacement — $300–$900

Work through these options from least to most expensive. Most B1727 failures trace back to a blown fuse, corroded connector, or worn switch — not the BCM itself.

How Much Does Fixing B1727 Cost?

Parts and labor rates at an independent shop in the United States typically fall within these ranges. If the fix involves only a fuse or wiring splice, expect to pay between $80 and $250. Replacing the adjustment switch or a failed motor runs $120 to $450 depending on the part price and labor time. A body control module repair or replacement is the costliest scenario at $300 to $900. Across all possible failure points, the total bill for B1727 generally lands between $80 and $900. Proper diagnosis before purchasing parts prevents unnecessary spending — the most expensive repair is rarely the correct first guess.

Can You Drive with B1727?

In most cases, B1727 poses no immediate safety risk and the vehicle remains fully driveable. Body system codes do not typically affect engine operation, braking, or steering. That said, if the seat malfunction leaves the driver's position uncomfortable or unreachable, it becomes a safety concern on longer trips. Additionally, if the underlying fault involves shared wiring that also controls exterior lighting, wipers, or central locking, those secondary systems may behave unpredictably. Use your judgment — short local drives are fine; a lengthy commute with compromised seat adjustment or unreliable lighting warrants prompt repair.