B1746
Mirror Passenger Horizontal Switch Circuit Open
Body Chassis/Safety Mirror Controls 🟢 Low — Fix at next service
💬
What This Actually Means
In plain language — no jargon

The passenger side mirror's horizontal adjustment switch has a broken electrical connection, like a light switch that won't complete the circuit. The mirror control module can't detect when you're trying to move the mirror left or right.

⚡
Symptoms You May Notice
3 known symptoms for this code
Passenger mirror won't adjust horizontally left or right
Mirror control button feels unresponsive or stuck
Warning light or fault code displayed on dashboard
🔬
Embedded Systems Insight
What the ECU/ECM is actually computing

The body control module monitors voltage continuity through the passenger mirror horizontal switch circuit. It expects a closed circuit with proper voltage when the switch is activated, and detects an open circuit when the connection is broken or interrupted.

Voltage & Parameter Thresholds

Parameter Normal Range Fault Condition
Switch Circuit Voltage 0V (closed) or 12V (open with key on) No voltage transition detected; circuit remains open
Circuit Continuity Continuity present when switch engaged No continuity; infinite resistance detected
🔧
Diagnostic & DIY Fix Guide
Check these in order — from cheapest to most complex
1
Mirror control switch connector
Inspect and reseat the electrical connector behind the mirror control panel for corrosion or loose pins.
2
Mirror control switch
Replace the faulty horizontal adjustment switch if connector cleaning doesn't resolve the open circuit.
3
Wiring harness section
Repair or replace damaged wiring between the switch and body control module if continuity test fails.