B1412

Code

ALFA ROMEO B — Body

Driver-side electric window motor short to positive

Brand: ALFA ROMEO

Type: B — Body

Views: UK: 6 EN: 5 RU: 12

AI status

Completed

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Page language: EN

Causes

Shorted wiring (insulation abrasion) to battery positive on driver window motor circuit
Faulty driver door connector (corrosion, bent pins touching positive)
Shorted or shorted-to-positive window switch or contacts
Failed/shorted window motor with internal short to positive
Faulty body/comfort control module (output stage shorted)
Blown or intermittent fuse/auto-reset protection caused by repeated short

Symptoms

Driver window does not move or moves only in one direction
Window operation erratic or only works with ignition/accessory on
Blown fuse or repeated fuse trips for power windows
Burnt smell or heat at the motor/connector when attempting operation
Related message or lamp from body/comfort module (loss of window function)

What to check

Read and record freeze-frame data and any additional DTCs from the body/comfort module
Visually inspect driver door wiring harness at hinge, grommet and connector for damage or pin contact
Check condition of driver window connector pins for corrosion, melting or pushed pins
Verify relevant fuses and relays for the power windows are intact and correctly rated
Disconnect the driver window motor and attempt operation to see if DTC clears or symptoms change
Measure voltage at motor connector with switch not operating and while operating (see signal parameters)

Signal parameters

Battery voltage at rest: ~12.0–12.8 V (engine off), ~13.5–14.8 V (engine running)
At motor connector with switch idle: near 0 V on both pins (or equal potential) — no drive voltage
When commanding window up: ~+12 V appears on one motor terminal and ~0 V on the other; polarity reverses for down
Stall / peak motor current: can reach 10–50 A depending on motor; sustained stall current indicates shorted/braked motor
Short-to-positive condition: permanent ~+12 V present on a motor terminal when circuit is inactive

Diagnostic algorithm

Record DTC and any related codes; clear codes and attempt to re-run to confirm persistence of B1412.
Inspect driver door harness at hinge and connector for visible damage, pin exposure or debris causing a short.
Check fuse(es) for window circuit; if blown, replace with correct rating and observe if it blows again when operating window.
With ignition on, disconnect driver window motor connector. Use DMM to check for battery voltage on each terminal with switch at rest. No sustained +12V should appear on a terminal when switch is inactive.
Operate the driver window switch while measuring voltage at the disconnected motor connector. Confirm polarity reversal and that voltage only appears while the switch is commanded.
If +12 V is present on a terminal with switch off, trace wiring back toward the switch and fuse/relay to locate short to battery positive (inspect splice points, accessory feeds).
If voltage behavior from the switch is normal, reconnect motor and measure current with clamp meter while operating. High/sustained stall current suggests motor internal short — consider motor replacement.
Swap driver and passenger switch/motor signals where practical (or use bench test) to isolate switch, motor, or module fault. Use service wiring diagrams to avoid incorrect swaps.
If wiring and motor check good but module outputs show permanent +12 V (or short to supply), test/replace the body/comfort control module per manufacturer procedures.
After repair, clear codes and test full window function through several cycles; re-scan to confirm DTC does not return.

Likely causes

Chafed harness where it passes through the door hinge/door sill making contact with battery positive
Connector pin pushed out and contacting a positive supply pin or bodywork
Motor brushes or internal wiring shorting to the motor case
Switch contacts welded/shorted to permanent 12V feed
Control module output transistor/bridge failure shorted to supply

Fault status

⚠️ Status

Driver-side window motor circuit detected short to battery positive — protective fault stored by body/comfort module.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.0 hours

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