Door Ajar / Open Warning Light

The door ajar warning light shows an overhead view of the car with one or more doors highlighted in red. It illuminates when a door, boot, or bonnet isn't fully closed. Usually this is self-explanatory — firmly close all doors and the light goes out.

When it won't go off with all doors closed:

A faulty door sensor (door ajar switch) is the most common cause. The switch is built into the door latch mechanism and can fail in the closed position — always reporting the door as open. This causes the interior light to stay on permanently and drains the battery.

Which door? The dashboard display usually shows which door is affected. The sensor is part of the door latch assembly — on some cars it's a separate switch, on others it's integrated into the latch. A new latch costs £20–60; labour adds 30–60 minutes.

Temporary fix: If you can identify the faulty door, some people apply a small piece of tape over the door pin to manually close the switch. This is a temporary workaround while awaiting repair.

Battery drain: A door ajar light staying on because of a faulty sensor keeps the interior lighting and body control module active. On some cars this will flatten a healthy battery overnight. Fix it promptly.