DTC B1D08-19: Left Trailer Direction Indicator - Circuit current above threshold: Action

NOTE: This DTC can be set due to an electrical fault in the trailer

Inspect the left trailer turn signal indicator for correct operation
Inspect the trailer socket and wiring harness for signs of damage or corrosion, rectify as necessary
Refer to the electrical circuit diagrams and check the left trailer turn signal indicator circuit for short circuit to ground. Repair the wiring harness as necessary