B1745
Mirror Passenger Horizontal Switch Circuit Failure
Body Chassis/Safety Mirror Control Circuit 🟢 Low — Fix at next service
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What This Actually Means
In plain language — no jargon

The passenger side mirror's horizontal (left-right) adjustment switch isn't communicating properly with the car's computer, similar to a broken remote control that can't send its signal. The ECU detects an electrical fault in the circuit that controls the mirror's side-to-side movement.

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Symptoms You May Notice
3 known symptoms for this code
Passenger mirror won't adjust left or right
Mirror adjustment buttons unresponsive or intermittent
Fault code appears without other mirror issues
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Embedded Systems Insight
What the ECU/ECM is actually computing

The ECU monitors the voltage signal from the passenger mirror horizontal switch circuit. It expects a clean digital or analog signal when the button is pressed, with proper voltage transitions between positions. A fault occurs when the signal is absent, stays at an abnormal voltage level, or shows no response to switch input.

Voltage & Parameter Thresholds

Parameter Normal Range Fault Condition
Switch Signal Voltage 5V (or 0V-5V logic transitions) No voltage change or stuck at 0V/12V
Circuit Resistance Less than 10 ohms per connection Greater than 50 ohms or open circuit
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Diagnostic & DIY Fix Guide
Check these in order — from cheapest to most complex
1
Mirror switch connector
Disconnect and reconnect the passenger mirror switch connector at the door panel to reseat any loose pins.
2
Wiring harness inspection
Check the wiring between the switch and ECU for visible damage, corrosion, or pinched wires along the door frame.
3
Passenger mirror switch assembly
Replace the switch assembly if connections are clean but the fault persists.