The actuator of your BMW Z3 is what allows you to operate the locks on the doors. If the door lock actuator begins to malfunction, you should replace it immediately in order to prevent any unwarranted entry or theft of your Z3. The actuator is hidden behind the Z3's door panel, so the panel must be removed in order to replace it. The replacement process can be completed in under an hour with the appropriate tools.
Use a socket wrench to disconnect your vehicle's battery by removing the negative cable.
Use a flathead screwdriver to pry off the clips securing the door panel to the door.
Peel off the plastic insulation from the door and raise the window as far as it will go.
Use a socket wrench to remove the two securing bolts on the door that hold in the lock.
Use a Torx screwdriver to remove the Torx screw from the outer window channel. Remove the 10-mm bolt from the channel with a socket wrench.
Disconnect the actuator's electrical wiring connector and remove its retaining bolts with a socket wrench. Remove the actuator from the door.
Attach a replacement actuator to the door and reinstall the retaining bolts. Reconnect the wiring connector and reattach the Torx screw and bolt to the window channel.
Reattach the plastic insulation and the door panel. Reconnect the battery.