What does it mean?
B1935 is a Body (airbags, seat belts, body electronics) fault code. It indicates: Passenger Door Lock/Unlock Switch Circuit Stuck .
Symptoms
- Doors lock or unlock by themselves, sometimes cycling repeatedly
- The passenger lock switch does nothing while the driver switch still works
- Key fob commands are ignored, or only work for some doors
- Parasitic battery drain because the module never goes to sleep with an input stuck active
- Interior lamps, chime or theft deterrent behaving oddly for no obvious reason
Likely causes
- Worn or contaminated switch contacts inside the passenger door switch pack, stuck in the closed position
- Water leaking past the door vapour barrier into the switch or its connector, causing corrosion
- Chafed or broken wire in the rubber boot between the door and the pillar, shorting the switch signal to ground
- Lock actuator with integrated contacts sticking, so the module never sees the input return to rest
- Aftermarket alarm or remote start wiring spliced into the lock circuit and holding the input on
- Failed input driver or pull-up inside the door control module or body control module
How to fix it
- Read the lock and unlock switch inputs in live data and confirm one stays active with nobody touching the switch
- Unplug the passenger door switch pack: if the input goes idle immediately the switch is at fault, if it stays active the harness or module is
- Measure the switch contacts with an ohmmeter in rest and pressed positions, the reading must change cleanly and return
- Flex the door jamb harness boot while watching live data to expose a chafed or broken conductor
- Inspect both connectors for green corrosion, moisture and spread terminals, then dry, clean and reseat them
- Remove any add-on alarm or remote start splices from the lock circuit and retest
- Replace the switch pack or repair the harness, leaving module replacement as the last step, then verify every lock function