What does it mean?
B1802 is a Body (airbags, seat belts, body electronics) fault code. It indicates: Driver Door Lock/Unlock Switch Circuit High .
Symptoms
- Driver lock switch is completely inoperative in both directions
- Locking works only from the remote, key or another door switch
- Code sets each time the switch is pressed
- Door lock indicator or convenience locking features stop working
- Fault comes and goes when the door is moved through its travel
Likely causes
- Open circuit in the switch signal wire or in its ground return
- Door switch pack connector unplugged, loose or with a backed-out terminal
- Broken conductor inside the flexible boot at the door hinge, worst with the door open
- Worn switch contacts that no longer close reliably
- Signal wire shorted to battery voltage after a repair or an accessory installation
- Missing or high-resistance ground for the switch pack
- Corrosion inside the switch caused by long-term moisture
How to fix it
- Back-probe the module input and press the switch while watching for a voltage change
- Check switch continuity in both lock and unlock positions with the connector off
- Verify the switch pack ground with a voltage drop test
- Perform a continuity test of the signal wire through the hinge boot, door open and closed
- With the module unplugged, check whether battery voltage is present on the signal wire
- Repair broken conductors in the boot and renew damaged terminals
- Replace the switch pack, and the door module only as a last step