Code Definition

B1740 — Mirror Driver Horizontal Switch Circuit Short To Ground

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

About B1740

B1740 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 B1740 is stored, the module has detected a short-circuit (voltage pulled to ground or to supply) 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.

B1740 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 Driver Door Module (DDM) or Body Control Module (BCM) monitors the driver side exterior mirror horizontal switch input line, which carries the switch state from the mirror selector back to the module. DTC B1740 is set when the module detects an unintended path to ground on this input circuit, indicating that the switch wire is shorted to chassis or signal ground somewhere between the switch and the module. The module expects to see the input transition between defined voltage levels as the switch is pressed, so a steady low or zero voltage that does not change when the switch is operated p...

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