What Does B1775 Mean?
B1775 indicates the Body Control Module (BCM) has detected a short-to-battery voltage condition in the driver's side power mirror upward movement circuit. This means the mirror up control wire is seeing constant 12V+ when it should be switched ground or lower voltage, preventing normal operation. The BCM monitors mirror motor circuits and sets this code when voltage remains high on the up command wire even when the mirror should not be moving.
Common Causes
40%
Damaged or chafed wiring in the door jamb area causing short to power wire
30%
Failed mirror motor assembly with internal short circuit
20%
Shorted mirror switch assembly providing constant voltage to up circuit
10%
Water intrusion or corrosion in mirror connector causing cross-circuit short
Diagnostic Steps
1
Step 1: Visually inspect the door jamb area where wiring passes from door to body for chafed, pinched, or damaged insulation on mirror harness wires, especially flex points that move with door operation
2
Step 2: Disconnect the driver's side mirror connector and measure voltage on the 'mirror up' control wire at the body harness side with mirror switch in neutral position using a multimeter - should read 0V, if 12V+ present the short is between BCM and connector
3
Step 3: If no voltage found at body harness, reconnect and backprobe the mirror motor connector while actuating the mirror up/down - check for constant 12V+ on up circuit regardless of switch position indicating failed mirror motor internal short
4
Step 4: Remove and inspect mirror control switch, check for internal short by measuring resistance between up circuit terminal and power supply terminal with switch in off position - should be open circuit (infinite resistance)
5
Step 5: Perform wiggle test on all door harness sections while monitoring voltage on up circuit wire to isolate intermittent short location, pay special attention to door hinge flex area
6
Step 6: After repair, clear codes, cycle mirror through full range of motion in all directions, and verify no voltage present on up circuit during neutral/other direction commands to confirm repair success
Estimated Repair Cost
$120 - $450
Parts + labor, varies by vehicle and location
B1775 indicates the Body Control Module (BCM) has detected a short-to-battery voltage condition in the driver's side power mirror upward movement circuit. This means the mirror up control wire is seeing constant 12V+ when it should be switched ground or lower voltage, preventing normal operation. Th...
The most common cause of B1775 (Mirror Driver Up Circuit Short To Battery) is: Damaged or chafed wiring in the door jamb area causing short to power wire
Typical repair costs for B1775 range from $120 to $450, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to continue driving as this only affects power mirror adjustment functionality. Mirror can typically still be adjusted manually or may be stuck in one position, which could impact visibility and should be repaired before long trips.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1775 to identify the root cause.
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Quick Info
Category
Body
System
Power Mirror Control System
Difficulty
Type
Manufacturer
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