Interior lamps

Off A Door contact B On C
If you set the switch to position B, the courtesy lamp will come on when you unlock or open a door or the luggage compartment lid. If you leave a door open with the ignition switch off, the courtesy lamp will go off automatically after some time to prevent the vehicle battery from discharging. To switch it back on, switch on the ignition for a short time.
The courtesy lamp will also come on when you switch off the ignition. It will go off automatically after a short time or when you start or restart the engine.
If you set the switch to position C with the ignition switch off, the courtesy lamp will come on. It will go off automatically after a short time to prevent the vehicle battery from discharging. To switch it back on, switch on the ignition for a short time.

If you switch off the ignition, the reading lamps will go off automatically after some time to prevent the vehicle battery from discharging. To switch them back on, switch on the ignition for a short time.

Off A On B
If you switch off the ignition, the vanity mirror lamps will go off automatically after a short time to prevent the vehicle battery from discharging. To switch them back on, switch on the ignition for a short time.
Test yourself
A quick Ford Focus quiz: every answer comes with an explanation and a link to the manual page.