Door Ajar Lamp Circuit Open
The door ajar warning lamp circuit has an open electrical connection, like a broken wire in a lamp's power cord. The ECU can't send power to illuminate the door ajar indicator light on the dashboard.
The ECU monitors the circuit resistance and voltage to the door ajar lamp during initialization and operation. It expects low resistance when commanding the lamp on and detects an open circuit (infinite resistance) when the wiring or lamp is broken. The ECU sets a fault code when it cannot complete the circuit or detect expected voltage changes.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Lamp circuit resistance | Less than 10 ohms when lamp powered | Greater than 10K ohms (open circuit detected) |
| Lamp supply voltage | 11-14V when commanded on | 0V or no voltage change detected |
Code B1324 is a low-severity fault. Your vehicle is generally safe to drive to a workshop for diagnosis. However, do not ignore it indefinitely — low-severity codes often indicate developing problems that become expensive if neglected. Book a diagnostic appointment within 2–4 weeks. If you notice any additional symptoms (rough running, power loss, unusual smells), treat it as higher priority.
Once the fault is repaired, B1324 can be cleared using any OBD-II scanner. Connect the scanner, navigate to "Clear Codes" or "Erase DTCs," and confirm. The check engine light turns off immediately.
The code will return if the root cause was not actually fixed. The ECM re-detects the fault within 1–3 drive cycles and sets the code again.