Mirror Passenger Up Circuit Failure
The passenger side mirror's up/down motor circuit isn't working properly, similar to a light switch that won't turn on even though the wiring is connected. The ECU detected an electrical fault preventing the mirror from moving upward.
The ECU monitors the voltage and current draw in the passenger mirror up/down motor circuit. It detects opens, shorts, or resistance faults by measuring whether proper current flows when the mirror switch is activated. If voltage doesn't reach expected levels or current draw is abnormal, a circuit failure is flagged.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Motor Circuit Voltage | 12-14V when activated | Below 8V or open circuit detected |
| Motor Current Draw | 2-5 amps during operation | Zero amps (open) or over 10 amps (short) |
Code B1782 is a low-severity fault. Your vehicle is generally safe to drive to a workshop for diagnosis. However, do not ignore it indefinitely — low-severity codes often indicate developing problems that become expensive if neglected. Book a diagnostic appointment within 2–4 weeks. If you notice any additional symptoms (rough running, power loss, unusual smells), treat it as higher priority.
Once the fault is repaired, B1782 can be cleared using any OBD-II scanner. Connect the scanner, navigate to "Clear Codes" or "Erase DTCs," and confirm. The check engine light turns off immediately.
The code will return if the root cause was not actually fixed. The ECM re-detects the fault within 1–3 drive cycles and sets the code again.