What Does B1420 Mean?
This code indicates the Body Control Module (BCM) has detected an abnormal voltage condition in the passenger side power window motor circuit, specifically a short to battery voltage. This means the window motor circuit is receiving constant battery voltage when it should not be, either through damaged wiring insulation, a failed window switch, or internal motor circuit failure. The BCM monitors window motor circuits and sets this code when it detects voltage present on the circuit when the window switch is not commanded.
Common Causes
45%
Damaged or chafed wiring harness causing short to battery voltage in window motor circuit
30%
Failed passenger window switch with internal short to power
15%
Faulty window motor with internal short circuit
10%
Failed window relay or BCM output driver stuck closed
Diagnostic Steps
1
Step 1: Perform visual inspection of passenger door wiring harness, particularly at door hinge area and window motor connector for damaged, chafed, or burned wiring that could be contacting battery voltage
2
Step 2: Disconnect passenger window motor connector and use a multimeter to measure voltage at motor connector (harness side) with ignition on and window switch in neutral position - should read 0V; if battery voltage is present, problem is in wiring or switch
3
Step 3: With motor still disconnected, disconnect passenger window switch and recheck voltage at motor harness connector - if voltage disappears, switch is faulty; if voltage remains, trace wiring between BCM and motor for short to power
4
Step 4: If no voltage found at motor connector with switch disconnected, reconnect switch and measure resistance across motor terminals (motor side of connector) - should read 3-8 ohms typically; if shorted (near 0 ohms) or shows continuity to ground with power applied, motor is internally shorted
5
Step 5: Repair or replace faulty component (wiring, switch, or motor), clear codes, and operate window through full up/down cycles multiple times to verify proper operation and confirm code does not return
Estimated Repair Cost
$150 - $650
Parts + labor, varies by vehicle and location
This code indicates the Body Control Module (BCM) has detected an abnormal voltage condition in the passenger side power window motor circuit, specifically a short to battery voltage. This means the window motor circuit is receiving constant battery voltage when it should not be, either through dama...
The most common cause of B1420 (Passenger Power Window Motor Circuit Short To Battery) is: Damaged or chafed wiring harness causing short to battery voltage in window motor circuit
Typical repair costs for B1420 range from $150 to $650, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to continue driving as this affects only passenger window operation. The window may operate erratically, remain stuck, or drain the battery if constantly powered. Repair at convenience but address promptly if window is stuck open for security and weather protection.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1420 to identify the root cause.
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Quick Info
Category
Body
System
Body Electrical System - Power Windows
Difficulty
Type
Manufacturer
Recommended Tools
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