Start by checking the "Possible Causes" listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector's pins.
The cost to diagnose the B1320 code is 1.0 hour of labor. The auto repair's diagnosis time and labor rates vary by location, vehicle's make and model, and even your engine type. Most auto repair shops charge between $75 and $150 per hour.
The Smart Junction Box (SJB) sends a voltage signal to the door ajar switches. The door ajar switch is closed with the door closed. When the door is opened, the signal to ground is interrupted indicating an open door to the SJB. The Diagnostic Trouble Code (DTC) sets when the SJB detects an open from the LH front door ajar input circuit.
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