The tailgate lock on a Citroen C4 is controlled electronically, like many of the C4's other components. If the tailgate lock becomes faulty, it may unlock at unwanted times or fail to lock at all times. A faulty tailgate lock may also result in the lock not being as secure as it once was. Replacing the tailgate locking unit with a new locking mechanism can solve a majority of tailgate lock problems on the Citroen C4.
Remove the two bolts on the right and left sides of the tailgate lock with the size 27 Torx wrench.
Pull the locking mechanism straight out to remove it.
Remove the green connector cable by pressing the release tab and pulling it straight out.
Connect the green connector cable to the new locking mechanism by pressing it into the connector compartment until it locks into place.
Position the new lock mechanism where the old one was.
Insert the two bolts and tighten with the size 27 Torx wrench.
To access the tailgate-locking mechanism, fold the rear seats down and enter toward the trunk.