B1744: Mirror Passenger Vertical Switch Circuit Short To Ground

What does B1744 mean?

B1744 is a diagnostic trouble code indicating "Mirror Passenger Vertical Switch Circuit Short To Ground". The ECU is detecting a voltage reading that is below the expected range in the doors & windows circuit. This typically points to a wiring short, a faulty sensor, or a grounding issue.

Symptoms you may notice

• Check engine light (MIL) illuminated on dashboard
• Intermittent warning lights
• Erratic gauge readings

Common causes

• Damaged or corroded wiring harness
• Loose or disconnected electrical connector
• Failed doors & windows sensor or actuator
• Blown fuse in the related circuit
• Poor ground connection

What should you do?

This code sits in the body control module or something wired through it. That module runs the unglamorous things you only miss when they stop: headlights, wipers, indicators, central locking. The car will usually drive, but check what has actually stopped working before you rely on it at night or in the wet.