1. Check the latch mechanism: The latch mechanism may be broken or damaged, preventing the door from latching properly. Inspect the latch for any signs of damage or wear and tear.
2. Check the strike plate: The strike plate is the metal piece on the door jamb that the latch engages with. Make sure that the strike plate is properly aligned and secured. If the strike plate is loose or misaligned, it can prevent the door from latching properly.
3. Check the door alignment: If the door is not aligned properly, it can put stress on the latch mechanism and prevent it from working properly. Check the door alignment by measuring the gap between the door and the door jamb on all sides. The gap should be even all the way around.
4. Check the door handle: The door handle may be loose or damaged, preventing it from engaging the latch mechanism properly. Inspect the door handle for any signs of damage or wear and tear.
5. Lubricate the latch mechanism: Over time, the latch mechanism can become dry and sticky, preventing it from working properly. Apply a lubricant, such as WD-40, to the latch mechanism to help it move more smoothly.
If you have checked all of these things and the interior door latch is still not working, you may need to replace the latch mechanism.
