B1108 — Central locking motor from the driver's door

Causes

• Electrical fault in the actuator circuit (open/short/intermittent).
• Failed or seized door lock motor/actuator.
• Corroded or poor connector/wiring (often at door hinge flex area).
• Blown fuse or failed relay feeding the actuator.
• Mechanical binding of latch/linkage preventing actuator movement.
• Faulty door module or body control module software/hardware.

Symptoms

• Driver door will not lock or unlock with remote/key/central command.
• Driver-door lock operates intermittently or only after multiple attempts.
• Loud grinding, clicking or no sound from driver-door area during lock/unlock.
• Other doors lock/unlock normally while driver door fails.
• DTC B1108 present and may be accompanied by other body/door module codes.
• Possible parasitic battery drain if actuator is stuck energized.

What to check

• Scan vehicle for stored codes in body/door modules and note freeze/frame data.
• Visually inspect fuses and relays related to central locking; replace if faulty.
• Inspect driver-door wiring harness through door jamb for chafing, broken wires or corrosion.
• Disconnect actuator connector and inspect pins for corrosion, damage or water.
• Listen for motor noise while commanding lock/unlock; compare with passenger side.
• Check operation of latch/linkages mechanically to ensure no binding.

Signal parameters

• Battery supply voltage to actuator: ~11–14 V (when command present).
• Motor coil resistance: typically low (a few ohms) — manufacturer-specific (expect continuity).
• Actuator current draw during movement: intermittent peak typically 0.5–5 A (overload indicates mechanical/electrical fault).
• Control signal: switched 12 V or ground output from door/body module or PWM; verify command present with a scope/multimeter during operation.
• Communication: door module should show normal CAN/LIN activity when commanding locks; loss of comms may prevent actuation.

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