To replace an automobile's car door lock cylinder, roll up the window, unlock the door, remove the inside door panel, remove the retaining clip on the cylinder, remove the cylinder, and insert the new lock. The procedure varies depending on whether the door window is manual or electronic. Manual windows require removal of the crank handle using a crank handle removal tool.
After removing the window crank handle as needed, remove the screws from the door handle tray and armrest. Set all of the removed parts to the side for reassembly later. Start at the low corners with a flat-head screwdriver, and remove the retaining clips attached to the inside door panel. Continue around the door until the panel is free, and move the panel out of the way.
Using a pair of needle-nose pliers, remove the retaining clip on the back end of the locking cylinder holding it in place. Disconnect the door lock indicator arm from the cylinder with the pliers. Push the cylinder from behind on the inside while pulling it forward from the outside until it is removed.
Place the rubber gasket around the new locking cylinder. Line up the cylinder slot with the door, insert the new lock, and reattach the locking indicator and retaining clip. Reassemble the door in reverse order.