To loosen the trunk lid lock, unlock the trunk and loosen the lock screws, and pull the lock out disconnecting its wiring connector and the link rod to which it is hooked. To the trunk lid lock cylinder, a trunk lid plastic cover should first be unclipped and then the lock cylinder link rod unclipped and the lock link rod balljoint disconnected. Unscrew the two retaining screws to take off the lock cylinder assembly on the trunk lid and regain the lock cylinder sealing ring. Slip the key into the lock, take pains in knocking away the retaining clip and removing the lock cylinder and sealing ring checking the sealing rings against a piece of furniture and replacing them, should they be worn or damaged. To install it, re-connect the wiring connector and firmly attach the link rod, and then fit the lock in the trunk lid and tighten the attaching bolts. Install the sealing ring to the lock cylinder and insert the same in the housing by means of the retaining clip and ensure the working of lock cylinder assembly. Install the lock cylinder assembly to the sealing ring, install it into the trunk lid and put the retaining screws in place, screwing it firmly. Attach the link rod balljoint back on the lock cylinder, reconnect the link rod firmly, test the operation of the lock assembly and fit the plastic cover on the trunk lid.