B1429

Code

Other B — Body

Lamp Seat Belt Circuit Short To Ground

Brand: Other

Type: B — Body

Views: UK: 30 EN: 65 RU: 37

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Page language: EN

Causes

Damaged/abraded wiring harness with insulation worn to ground near lamp, connector, or chassis
Corroded or bent connector pins creating unintended ground
Failed seat belt warning lamp (shorted bulb or LED module)
Faulty seat belt buckle switch or sensor with internal short to ground
Defective body/control module (BCM) driver transistor or internal short to ground
Aftermarket equipment or recent repairs that disturbed wiring and created a short

Symptoms

Seat belt warning lamp illuminated continuously or behaves incorrectly
Seat belt reminder chime may operate incorrectly or remain on
Lamp may not respond to buckle/unbuckle (no change)
DTC B1429 stored in body/control module, may be accompanied by other seat belt codes
Possible intermittent fault when steering/suspension moved if wiring is being pinched

What to check

Retrieve freeze-frame and live data with a scan tool; confirm lamp status and related seat belt inputs
Visually inspect wiring, connectors, and lamp assembly for damage, corrosion, or loose pins
Inspect routing where harness contacts metal edges, dash, or steering column for chafing
Disconnect the battery or follow manufacturer safety procedures before probing connectors if required
Disconnect the lamp/indicator connector and check if the code clears or lamp behavior changes (isolates lamp vs harness/module)
Measure voltage and continuity at the lamp connector and control module pin with a multimeter/back-probe

Signal parameters

Lamp supply voltage when commanded ON: ~11–14 V (vehicle battery voltage) at lamp connector (varies by vehicle)
Voltage to control pin when lamp OFF: should be near open/high impedance; short-to-ground condition yields ~0 V at lamp supply pin
Resistance to ground from lamp feed with connector disconnected: normally high (kΩ); short to ground shows near 0 Ω
Indicator driver current: typically well under 1 A for modern lamps; excessive current may indicate incandescent bulb or short

Diagnostic algorithm

Read and record freeze-frame and related DTCs with a scan tool; note lamp state and any relevant inputs.
Perform a visual inspection of the seat belt lamp, connector, wiring harness, and routing for damage, corrosion, or recent repair points.
Disconnect the seat belt lamp/indicator connector. Clear the code, then cycle ignition and observe: if the code does not return, suspect lamp/connector/harness downstream of module.
With ignition ON, back-probe the lamp feed pin at the connector. Verify voltage when the module commands the lamp ON and OFF using a scan tool to command lamp if possible.
If lamp feed is ~0 V at connector with ignition ON and lamp disconnected, check continuity from the lamp feed to the body/control module output pin to isolate where the short occurs.
If short is present between feed and ground at harness side, isolate sections by disconnecting intermediate connectors and testing each section for continuity to ground.
If the short is isolated to the lamp assembly, replace lamp/indicator. If isolated to wiring, repair damaged wiring and replace or repair connectors as necessary.
If wiring and lamp check good, test or replace the body/control module output driver or consult manufacturer procedures; consider module replacement only after wiring and lamp verified.
After repair, clear DTCs, verify lamp operation and perform a road/usage cycle to confirm the fault does not return.

Likely causes

Chafed harness near dash or instrument cluster causing lamp feed short to chassis ground
Corroded/contaminated lamp connector or pin contacting ground
Faulty lamp (internal short) or lamp assembly wiring fault

Fault status

⚠️ Status

Seat belt lamp circuit short to ground detected. Lamp may be on continuously or non-functional. Fault stored in body/control module; inspection of lamp, wiring, connectors, and module recommended.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.0 hours