Code Definition

B12FF (15-48) — Rear Door Switch Illumination Circuit – Circuit Short to Battery or Open

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

About B12FF

B12FF 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 B12FF is stored, the module has detected an open (broken or disconnected) electrical path in the monitored circuit; and 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.

B12FF 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) on the affected Ford controls and monitors the illumination supply for the rear door switch backlighting, typically driven as a low side or PWM controlled output so the BCM can dim the switch lighting in step with the dash panel illumination. DTC B12FF:15 48 reports a fault on this rear door switch illumination circuit, with the :15 failure type byte denoting a circuit short to battery and the trailing 48 status byte indicating the fault is currently stored as previously set rather than always active. The combined effect described in Ford service literature is tha...

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