A car-door lock is an integral part of keeping your car safe when you're not around. So when you find your car-door lock isn't working properly, it can be quite worrying. Repairing the lock requires some physical aspects, so it may not be suitable for everyone to try.
Use a screwdriver to carefully remove the small screws holding the door handle in place. Remove the plastic or metal handle using the pliers.
With the lock now exposed, remove the small metal rod with your pliers, being careful not to damage the lock core in the process.
Cover the cloth in the cleaning fluid and wipe clean any dirt in the lock core, making sure to also wipe clean the hole which you took the small rod from.
Insert the new rod into the lock core, and use the wrench to press down on the rod and lock to click into place. You can buy a small metal rod to use for this project from most hardware stores and DIY outlets.
Reattach the plastic or metal handle and wipe any marks away with the cloth.
If you have trouble gaining access to the door handle, you might consider removing the car door.