Code Definition

B1807 — Lamp Tail Output Circuit Open

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

About B1807

B1807 is a manufacturer-specific body diagnostic trouble code. It belongs to the B-prefix family of codes, which covers body, interior, airbag, or comfort-electronics faults.

When B1807 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.

B1807 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) controls the tail lamp output and monitors the circuit for proper current flow when the lamps are commanded on with the parking lights or headlights. DTC B1807 sets when the BCM detects an open circuit specifically on the tail lamp output, meaning current cannot flow through the load when the lighting switch is active. Because the tail lamp output typically feeds multiple low wattage filaments in parallel including both rear corners and the side markers, an open circuit fault can be triggered by a single failed bulb if the BCM is configured to expect a specific mi...

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