B1426

Code

Other B — Body

Lamp Seat Belt Circuit Short To Battery

Brand: Other

Type: B — Body

Views: UK: 25 EN: 41 RU: 27

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Page language: EN

Causes

Damaged wiring insulation with conductor contacting battery/constant power
Shorted or incorrectly routed harness near body/chassis points
Faulty seat belt buckle switch or sensor internally shorted to battery
Corroded or bridged connector terminals at the lamp, buckle, or BCM/module
Faulty instrument cluster or body control module driving the lamp

Symptoms

Seat belt warning lamp stays ON constantly
Lamp remains on even when belts are buckled
Possible blown fuse for instrument/comfort circuit
Occasional chime or incorrect seat-belt status messages
Possible increased battery drain with ignition off

What to check

Scan for stored codes and confirm B1426 and any related codes
Visually inspect wiring harness along seat, B-pillar and under dash for damage
Check fuses for the instrument cluster/body control circuits
Back-probe the seat belt lamp circuit connector and buckle switch connector
Disconnect connectors (lamp, buckle switch, BCM/cluster) to isolate circuit section

Signal parameters

Circuit voltage with ignition ON and lamp commanded OFF: approximately 0 V (should not be battery voltage)
Circuit voltage with lamp commanded ON: near battery voltage (~11–14 V)
Standby current on the circuit: typically low (tens of mA); unexpected high current suggests a short
Resistance from circuit to battery positive with connectors disconnected: should be open/very high unless lamp is intentionally powered

Diagnostic algorithm

Read and record all codes; note freeze frame data.
Turn ignition OFF. Visually inspect harnesses and connectors from the seat belt buckle to the instrument cluster and body control module.
Check relevant fuses; replace any blown fuses and see if they blow again (indicates short).
With ignition ON, back-probe the lamp circuit and measure voltage. If battery voltage is present when lamp should be off, suspect a short to battery upstream.
Disconnect the seat belt buckle connector. If the lamp goes out or the short clears, suspect the buckle switch or its wiring. If not, continue isolating toward the cluster/BCM.
Disconnect the instrument cluster/body control module connector for the lamp output; if the short clears, test the module output for internal short or use a test lamp/resistor to verify.
Perform continuity/resistance checks between the lamp circuit and battery positive to find short location. Wiggle harnesses while monitoring to detect intermittent shorts.
Repair or replace damaged wiring, connectors, buckle switch, or faulty module as required. Use correct OEM parts and wiring repair techniques (solder, heat-shrink, or proper crimping).
After repair, clear codes, verify lamp operation in all states (key on/off, buckled/unbuckled), and road test to confirm code does not return.
Safety note: Seat belt pretensioners and associated circuits may be part of the supplemental restraint system (SRS). Follow manufacturer procedures for disabling the battery and waiting the recommended time before servicing SRS or connector areas.

Likely causes

Pinched or chafed harness where it passes through a body panel or seat
Seat belt buckle switch failed internally, supplying battery voltage to lamp circuit
Connector contamination causing +12V to feed back into the lamp circuit
Previous repair left a wire swapped or tied into a constant hot feed
Failed cluster/module output transistor shorted to battery

Fault status

⚠️ Status

Lamp Seat Belt Circuit Short To Battery — seat belt warning lamp circuit is receiving battery voltage when it should not; inspect for wiring short to +12V, faulty buckle switch, or module failure.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.5 hours