What Does B1405 Mean?
This code indicates the Body Control Module (BCM) has detected that the driver's power window down circuit is experiencing an unintended voltage feed from the battery. The BCM monitors the window switch and motor circuits, and has determined that battery voltage is present on the down circuit when it should not be, typically indicating a short to power condition. This creates a situation where the window may operate unexpectedly or the circuit protection may be compromised.
Common Causes
45%
Damaged or chafed wiring harness in door jamb area causing short to power wire
30%
Faulty driver window switch with internal short to battery voltage
15%
Water damage or corrosion in door switch panel causing cross-circuit short
10%
Failed window motor with internal short or damaged BCM window control relay
Diagnostic Steps
1
Step 1: Perform visual inspection of driver door wiring harness, particularly in the door jamb flex area. Check for pinched, chafed, or damaged wires that may be contacting power sources. Inspect window switch connector for water intrusion, corrosion, or melted terminals.
2
Step 2: Disconnect the driver window switch connector and measure voltage at the BCM-side connector terminal for the window down circuit using a digital multimeter. Should read 0 volts with ignition on; if battery voltage is present, the short is between the BCM and switch connector in the harness.
3
Step 3: If no voltage found at switch connector, reconnect and disconnect the window motor connector. Measure resistance between the down circuit wire and battery positive. Should read infinite resistance (open circuit); continuity or low resistance confirms short to power in motor or wiring downstream of switch.
4
Step 4: Test the window switch itself by removing it from the door panel and performing a bench test with multimeter in ohms mode. Activate the down function and verify proper switch operation with no unintended continuity to power terminals. Replace switch if internal short is detected.
5
Step 5: If all wiring and components test normally, suspect BCM internal fault or circuit board corrosion. Check BCM connector terminals for corrosion and proper seating. Verify ground circuits are intact with less than 0.5 ohms resistance to chassis ground.
6
Step 6: After repair, clear codes, cycle window operation through full range multiple times, and verify code does not return. Monitor live data for window circuit voltage to confirm proper operation under all switch positions.
Estimated Repair Cost
$100 - $450
Parts + labor, varies by vehicle and location
This code indicates the Body Control Module (BCM) has detected that the driver's power window down circuit is experiencing an unintended voltage feed from the battery. The BCM monitors the window switch and motor circuits, and has determined that battery voltage is present on the down circuit when i...
The most common cause of B1405 (Driver Power Window Down Circuit Short To Battery) is: Damaged or chafed wiring harness in door jamb area causing short to power wire
Typical repair costs for B1405 range from $100 to $450, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to continue driving as this affects only convenience features. However, the window may operate unexpectedly or not at all, which could be a security concern. The short circuit condition could potentially drain the battery or damage the BCM if left unrepaired for extended periods.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1405 to identify the root cause.
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Quick Info
Category
Body
System
Body Control and Convenience Systems
Difficulty
Type
Manufacturer
Recommended Tools
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