The engine immobiliser is armed automatically a short time after you have switched the ignition off.
The indicator in the instrument cluster will flash to confirm that the system is operating.
Ford Focus Heater Core
Item
Part Number
Description
1
—
Climate control harness electrical connector (part of 18B604)
2
—
Heater core tube cover screw (2 required)
3
—
Heater core tube cover (part of 19B555)
4
—
Heater tube ...