Code
B1335
FIAT
B — Body
Right rear door open circuit
Views:
UK: 4
EN: 7
RU: 5
AI status
Completed
Completed
100%
Causes
- Broken or chafed wiring in door harness (hinge area)
- Corroded or loose connector at door or body harness
- Failed door ajar/contact switch or latch switch
- Water intrusion causing open/short or corrosion
- Poor ground or power supply to the switch circuit
- Intermittent connection from wear or previous repairs
Symptoms
- Right rear door open warning light or message on dash
- Interior lights may remain on or not turn off
- Chime/door ajar warning sounding or intermittent
- Central locking or power functions may not behave correctly for that door
- Possible parasitic battery drain if interior lights stay on
What to check
- Read and record freeze-frame/live data for B1335 with a scan tool; clear code and attempt to reproduce
- Visually inspect right rear door latch area, switch, and wiring harness through door hinge boot
- Check and reseat connectors at the door and body harness; inspect for corrosion or bent pins
- Operate the door latch/switch manually while observing live data or continuity
- Perform a wiggle/stress test on the wiring while monitoring the circuit for intermittent changes
- Measure voltage at the switch connector and at the BCM input with connector connected and disconnected
Signal parameters
- When door closed: switch typically shows continuity to ground (≈0–1 Ω) or voltage near 0 V on the BCM input (if switch grounds the line)
- When door open: input should be open/high impedance or pulled to supply voltage through pull-up (typically near battery voltage or a logical HIGH depending on design)
- Open-circuit condition: very high resistance/infinite Ω or floating voltage on the input
- Diagnostic current is very low; primary checks are continuity, resistance, and voltage levels at known states
- Expect the BCM input to switch cleanly between defined voltage levels when the latch is operated
Diagnostic algorithm
- Connect a scan tool, read B1335 and any related codes. Note live data for the right rear door status.
- Clear the code, operate the right rear door open/close and watch if the code returns or the live status changes.
- Visually inspect the door latch, ajar switch and wiring boot in the B-pillar for chafing, pinched wires, or corrosion.
- With ignition on, probe the door switch connector: verify expected voltage/ground behavior with door open vs closed.
- Check continuity between the switch and the BCM input pin with connectors disconnected; move the harness through full travel while observing for opens.
- If an open is found in the harness, repair by replacing or splicing the damaged section, protecting with grommets and routing to avoid hinge stress.
- If switch is faulty or sticky, replace the door latch/switch assembly per vehicle procedure.
- After repairs, erase codes and perform several open/close cycles to confirm the fault does not return and monitor for intermittent issues.
- If wiring and switch pass tests but the code persists, follow manufacturer procedures to test the BCM input or perform module substitution as a last resort.
Likely causes
- Damaged wiring in the door hinge area (most common)
- Failed or stuck door ajar / latch switch
- Corroded or poorly seated connector at the door
- Water ingress causing intermittent open circuit
Fault status
Status
Right rear door open circuit detected (B1335). The body control module reports an open or intermittent condition on the right rear door input. Inspect door switch, connectors, and wiring in the hinge/boot area; repair or replace faulty components. Verify operation and clear the code.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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