The lock indicator light on a 2003 Saturn Ion, usually shaped like a padlock, indicates the status of your car's doors and/or trunk. A solid light usually means the doors and trunk are locked. A flashing light often means there's a problem with the locking system – perhaps a door isn't fully closed, there's a malfunction in the system itself, or the alarm is triggered. Sometimes a flashing light can be a part of the alarm arming/disarming sequence.
If the light is behaving erratically or staying on when you expect it to be off, it's best to check all doors and the trunk to ensure they're securely closed. If the problem persists, you should consult your owner's manual or a mechanic, as there might be a fault in the locking mechanism or the associated wiring.
