Code Definition

B1734 — Mirror Driver Vertical Switch Circuit Open

System: Body  |  Type: Manufacturer-Specific  |  Make: Ford

About B1734

B1734 is a manufacturer-specific body diagnostic trouble code recorded for Ford vehicles. It belongs to the B-prefix family of codes, which covers body, interior, airbag, or comfort-electronics faults.

When B1734 is stored, the module has detected an open (broken or disconnected) electrical path in the monitored circuit.

Scanning & clearing: Body (B) codes are often stored in the body control module, airbag module, or climate module. A basic OBD-II tool usually will not read body codes — an enhanced or OEM-level scan tool is typically required.

B1734 is a manufacturer-specific code. The same code string on a different make may have a different meaning. Always confirm the code's definition against the vehicle's service information for the specific make and model under test.

Code Information

The Body Control Module (BCM) monitors the driver side mirror vertical adjustment switch through a dedicated input circuit. DTC B1734 sets when the BCM detects an open circuit on the driver mirror vertical switch input, meaning the switch is not pulling its input line to the expected state when the driver attempts to adjust the mirror up or down. The switch is typically located in the driver door switch pack or armrest panel and signals the BCM (or smart driver door module) to drive the mirror motor in the corresponding direction. When this code is set, the driver mirror will not respond to ve...

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