Sometimes the sliding door may have a latch that works by sliding a small notch up and down.
Fixing sliding door latch.
These locks are important for keeping your patio doors secure so it s important that you replace yours promptly if it s not working while you might need to completely replace your lock it s possible you just need to replace the latch.
As a house settles door latches and strike plates sometimes become misaligned so doors won t latch shut.
Because sliding patio doors are used a lot it s common for their locks to occasionally jam or break.
Once you get the key in the lock it may become difficult to turn the cylinder.
If the movement has been slight there s a very simple fix for the problem.
It might become difficult to insert your key into an old sliding door lock over time.
Try applying lubricant such as a petroleum based oil or wd 40 in the area to see if that works.
Don t leave the door unattended until the stop is installed roll the door to within a half inch of the latch side jamb then turn the roller adjustment screws until the door is parallel to the jamb.
How to repair a sliding door lock.
Usually you have to push the door in and either pull up or press down on the doorknob in order to get the door latch to catch in the strike plate.
This simple diy trick may solve your issues.