You should be familiar with the steps to be taken before unhooking the battery. There are several main components of the central locking system, which are the convenience system central control unit, which is placed behind the luggage compartment trim, door control unit, which is placed in the window regulator motors and the electric door lock actuator, which is placed in the door locks, tailgate lock actuator that is placed in the tailgate with the release button, anti-theft alarm horn, which is located under the right-hand front wheel arch, bonnet contact switch that is placed on the bonnet lock, and a remote control transmitter, which is placed on the ignition key To dismount the convenience system control unit, remove the right hand trim of the luggage compartment, loosen the retaining nuts, dismount the plastic mounting bracket, disconnect the wiring and slide out the control unit. In the case of the door control unit, the window regulator motor should be removed. You will need to remove the right-hand trim of the luggage compartment, wiring, loosen the retaining screws, and slide the actuator forward to take out the electric door lock actuator. With tailgate lock actuator, just remove it. To reach the anti-theft alarm horn, turn off the ignition, engage the handbrake, lift the front of the car, use axle stands to support the car, remove the right-hand front roadwheel, the wheel arch liner, drill the pop rivets fastening the horn, and unscrew the wiring. In the case of the bonnet contact switch there is the bonnet lock which needs to be pulled out and the switch is pushed in the slotted holes. To change the remote control transmitter battery, a screwdriver is needed to separate the transmitter unit and the key, open the covers, and scrape out the battery, taking note of the orientation. The process of refitting involves the opposite of removal, which is to install pop rivets and install the anti-theft alarm horn, and during this process, make sure that the central locking system is functional after the procedure.