Code Definition

B1691 — Autolamp Delay Circuit Short To Battery

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

About B1691

B1691 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 B1691 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.

B1691 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 B1691 code is set when the Body Control Module (BCM) or Light Control Module detects that the autolamp delay control input is shorted to battery voltage. The autolamp delay circuit normally sees a varying signal voltage corresponding to the position of the dash mounted delay control switch, and the BCM compares that voltage against expected ranges. When the input pin reads a steady high voltage above the expected operating range, the BCM concludes there is a short to battery somewhere on the signal wire or within the switch itself. The most common results are loss of the autolamp delay fun...

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