What Does B1745 Mean?
This code indicates that the Body Control Module (BCM) has detected a fault in the electrical circuit controlling the horizontal adjustment of the passenger side mirror. The BCM monitors switch inputs and has identified an open circuit, short circuit, or abnormal resistance in the switch circuit that commands left/right mirror movement. This is a manufacturer-specific body code related to the power mirror control system.
Common Causes
40%
Faulty passenger mirror adjustment switch with internal contact failure or corrosion
30%
Damaged or broken wiring between mirror switch and BCM or mirror motor
20%
Corroded or loose electrical connector at switch, BCM, or mirror assembly
10%
Failed Body Control Module with internal circuit fault
Diagnostic Steps
1
Step 1: Perform a visual inspection of the passenger mirror switch assembly for physical damage, moisture intrusion, or burned contacts. Test switch functionality manually and listen for mirror motor operation in all directions except horizontal.
2
Step 2: Using a digital multimeter, backprobe the mirror switch connector while operating the horizontal adjustment. Verify voltage changes between ground and signal voltage (typically 0V, 5V, or 12V depending on position) at the switch output terminal during left/right commands.
3
Step 3: Inspect and wiggle-test all wiring harnesses between the door jamb and door panel, checking for broken wires, chafing, or pinched conductors. Pay special attention to the door hinge area where wires flex repeatedly.
4
Step 4: Disconnect the mirror switch connector and measure resistance across the horizontal switch terminals while cycling the switch through all positions. Compare readings to manufacturer specifications (typically 0-5000 ohms depending on position, infinite when open).
5
Step 5: If switch and wiring test normal, access the BCM connector and measure continuity from the switch harness connector to the BCM input pin with all connectors disconnected. Verify less than 5 ohms resistance and no shorts to ground or power.
6
Step 6: After repairs, clear the code, cycle the mirror adjustment through all positions multiple times, and verify the code does not return. Test mirror operation in all directions to confirm full functionality.
Estimated Repair Cost
$75 - $450
Parts + labor, varies by vehicle and location
This code indicates that the Body Control Module (BCM) has detected a fault in the electrical circuit controlling the horizontal adjustment of the passenger side mirror. The BCM monitors switch inputs and has identified an open circuit, short circuit, or abnormal resistance in the switch circuit tha...
The most common cause of B1745 (Mirror Passenger Horizontal Switch Circuit Failure) is: Faulty passenger mirror adjustment switch with internal contact failure or corrosion
Typical repair costs for B1745 range from $75 to $450, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to continue driving. This fault only affects passenger mirror horizontal adjustment convenience and does not impact vehicle safety systems or driveability. Repair at your convenience, though proper mirror adjustment is important for safe lane changes.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1745 to identify the root cause.
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Quick Info
Category
Body
System
Body Control System / Power Mirror System
Difficulty
Type
Manufacturer
Recommended Tools
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