B1742
Mirror Passenger Vertical Switch Circuit Open
Body Chassis/Safety Mirror Control 🟢 Low — Fix at next service
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What This Actually Means
In plain language — no jargon

The passenger side mirror's vertical motor circuit has an electrical break, like a cut wire preventing a light switch from working. The ECU can't send signals to move the mirror up and down.

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Symptoms You May Notice
3 known symptoms for this code
Passenger mirror won't move vertically (up/down)
Mirror control switch unresponsive for vertical adjustment
Dashboard warning light or fault indicator illuminated
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Embedded Systems Insight
What the ECU/ECM is actually computing

The ECU sends a voltage signal through the vertical motor circuit and monitors for proper current draw and voltage feedback. It detects an open circuit when no current flows despite commanded voltage, indicating a break in the wiring or switch path.

Voltage & Parameter Thresholds

Parameter Normal Range Fault Condition
Circuit Voltage 12V signal with 0.5-2A current draw 12V signal with 0A current (open circuit detected)
Switch Resistance 50-500 ohms when activated Infinite resistance (open)
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Diagnostic & DIY Fix Guide
Check these in order — from cheapest to most complex
1
Mirror control switch connector
Inspect and reseat the passenger mirror switch connector at the door panel for corrosion or loose pins.
2
Mirror vertical motor wiring harness
Check the wire bundle running to the passenger mirror for breaks, pinches, or damaged insulation.
3
Passenger mirror motor assembly
Replace the vertical motor if wiring and connectors test good, as internal motor contacts may be open.