ok, then all you need is
cover:
- platform: template
covers:
garage_door:
device_class: garage
friendly_name: "Garage Door"
value_template: "{{ is_state('switch.garasjeport_sensor_3', 'on') }}"
open_cover:
service: switch.turn_on
entity_id: switch.garasjeport
close_cover:
service: switch.turn_on
entity_id: switch.garasjeport
stop_cover:
service: switch.turn_on
entity_id: switch.garasjeport