What Does B1776 Mean?
This code indicates the Body Control Module (BCM) has detected a short to ground in the driver's side power mirror vertical upward movement circuit. The BCM monitors the motor control circuits and sets this code when it detects abnormally low resistance or voltage on the mirror up command wire, indicating current is flowing directly to ground instead of through the motor. This prevents the mirror from tilting upward and may cause fuse failure or BCM damage if left unaddressed.
Common Causes
45%
Damaged or chafed wiring in the door jamb area where harness flexes during door opening/closing, causing insulation wear and exposed wire contact with ground
30%
Failed mirror motor assembly with internal short to ground in the vertical adjustment motor windings
15%
Moisture intrusion into mirror housing or door-mounted mirror switch causing corrosion and short circuit path to ground
10%
Faulty Body Control Module with internal driver circuit failure on mirror up output
Diagnostic Steps
1
Step 1: Perform visual inspection of driver door harness at hinge area and mirror housing for obvious chafing, pinching, or water damage. Wiggle harness while observing scan tool live data to see if code resets intermittently.
2
Step 2: Disconnect driver mirror connector and measure resistance between the mirror up control wire (typically identified in wiring diagram) and ground with digital multimeter. Should read open circuit (OL); any continuity confirms short to ground in harness or mirror.
3
Step 3: If short exists at mirror connector, disconnect mirror motor and recheck resistance. If short disappears, mirror motor is faulty. If short remains, trace and isolate wiring harness through door jamb to locate damaged section.
4
Step 4: If no short found at mirror connector in Step 2, backprobe BCM connector at mirror up control pin with multimeter set to resistance. Check for short to ground. If present here but not at mirror, internal BCM fault exists.
5
Step 5: After repair, clear codes and actuate mirror up function using switch while monitoring BCM commanded outputs and actual mirror movement. Verify no codes return and full range of motion is restored.
Estimated Repair Cost
$100 - $600
Parts + labor, varies by vehicle and location
This code indicates the Body Control Module (BCM) has detected a short to ground in the driver's side power mirror vertical upward movement circuit. The BCM monitors the motor control circuits and sets this code when it detects abnormally low resistance or voltage on the mirror up command wire, indi...
The most common cause of B1776 (Mirror Driver Up Circuit Short To Ground) is: Damaged or chafed wiring in the door jamb area where harness flexes during door opening/closing, causing insulation wear and exposed wire contact with ground
Typical repair costs for B1776 range from $100 to $600, depending on the vehicle, location, and whether you do it yourself or go to a shop.
This is safe to drive as it only affects mirror adjustment functionality and does not impact vehicle operation or safety systems. Repair can be scheduled at convenience, though prolonged operation may risk BCM damage or blown fuses if short is severe.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1776 to identify the root cause.
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Quick Info
Category
Body
System
Body Control and Accessories
Difficulty
Type
Manufacturer
Recommended Tools
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