Today I tried to lock my door and it wouldn't budge. I didn't want to force it so I sprayed some wd-40 in the hole hoping maybe it wold help. Now when I try to lock the door the security light goes on but the door is still unlocked. Any suggestions?

 

open the door and remove the door panel. Check the linkage to ensure they all move correctly.

 

If the security system activates, you know that the lock cylinder is moving, so pretty much all that's left is the rod to the lock.

A visual inspection should make it clear pretty quickly.