How do you switch off the car alarm on the alfa 156 without the fob?

To switch off the car alarm on an Alfa 156 without the fob, you can try inserting the key into the driver's side door lock and turning it to the unlock position. If that doesn’t work, you can disconnect the car battery for a few minutes, which may reset the alarm system. Alternatively, you could locate the alarm control unit and disconnect it manually, though this might require some technical knowledge.