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 B1804 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 Body Control Module (BCM) monitors the Lamp Turn Signal Rear. The BCM sets the OBDII code when the Lamp Turn Signal Rear is not to factory specifications.
Need more information on how to fix the B1804 code? Get Access to Factory Service Manuals
Get the B1804 code diagnosed by a professional: Find a repair shop in your area