B1403

Code

ALFA ROMEO B — Body

Driver window closing circuit

Brand: ALFA ROMEO

Type: B — Body

Views: UK: 3 EN: 11 RU: 5

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Open circuit or broken wire in the driver window close switch circuit
Short to battery or short to ground in the close circuit
Corroded/damaged connector at switch, motor or door control module
Faulty driver window switch (mechanical or internal electrical failure)
Faulty window motor or window regulator (seized or excessive current draw)
Faulty door control module / body control module (BCM) or software fault

Symptoms

Driver window will not close or is inoperative in the close direction
Intermittent operation or works in one direction only
Slow window movement or abnormal noise from regulator/motor
Stored B1403 DTC and possibly related body module warnings
Blown fuse when operating the window (in some cases)
Automatic one-touch/anti-pinch function not working

What to check

Read and record freeze-frame, related DTCs and live data with a diagnostic scanner
Verify battery voltage is normal (12–14 V) and inspect main fuses/relays for the power windows
Inspect door wiring harness and connectors for corrosion, damage, chafing or water ingress
Operate window while observing wiring/connectors for arcing or movement
Check switch function: verify continuity and that switch outputs change state when operated
Measure voltage at the window motor and at the switch while commanding close/open

Signal parameters

Switch output: toggles between 0 V (ground) and battery voltage (~12 V) when activated
Motor supply voltage: near battery voltage (~11–14 V) during movement command
Motor stall/current draw: brief spike is normal; significant continuous high current indicates binding or short (typical range varies by vehicle, often several amps under load)
Continuity: close-circuit wiring should show low resistance (< a few ohms between switch and motor terminals when connected)
Resistance: window motor windings typically show low ohms (compare left vs right side for anomalies)

Diagnostic algorithm

Connect a suitable scan tool. Read and record B1403 plus any other stored codes and live data for the driver door/BCM.
Attempt to operate the driver window while observing the reported status in the scan tool and listening/looking for motor action. Note whether code sets immediately or intermittently.
Visually inspect the driver door area: check the switch, wiring grommet between door and body, connectors, and the motor/regulator for damage or water ingress.
Check fuses and relays related to the power windows. Replace any blown items and retest.
With ignition ON, measure voltage at the switch connector and at the motor connector while commanding the window to close. Verify that the expected voltage appears and that grounds are solid.
Test switch continuity with a multimeter to verify the switch properly changes circuit paths when actuated.
If voltage from the module reaches the motor but the motor does not run, disconnect the motor and apply battery voltage directly (briefly) to test motor operation. If motor fails to run or draws excessive current, replace motor/regulator.
If motor works when directly powered but no correct signals from the door control module, inspect wiring back to the module and check grounds. Pin-probe module connector for expected signals.
Repair any damaged wiring/connectors, clean corroded terminals, and re-secure harnesses. Replace faulty switch, motor, or module as indicated by tests.
Clear codes, perform function test and repeat operations several cycles to confirm repair. Re-scan for any reoccurring faults.

Likely causes

Faulty driver window switch or its connector
Damaged wiring/connector between switch and door control module/motor
Faulty window motor or regulator drawing excessive current
Corroded connector at motor or door module
Faulty door control module or software anomaly

Fault status

⚠️ Status

Driver window closing circuit fault detected (B1403). Check switch, motor/regulator, wiring and door control module. Automatic closing may be disabled until fault is corrected.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-3.0 hours

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