Door lock

I caused a "C" like thing in the door lock to snap to a closed position and now the "C" is an "O" and won't let the door latch to close. How do I fix this? I was trying to figure out why my key wont unlock the door even though i hear the mechanism working.The handle won't even work. 1994 Chevy lumina van automatic door locks and windows

 

I think what you are describing is the actual latch in the door that closes on the round part that is mounted on the body door opening. To open it you must hold the door latch handle in the open position and at the same time use something to open the latch to the open position, going from the "O" to the "C" position. Now if the key doesn't unlock the door you may have to get into the door and look for possible linkage that is unhooked or a faulty latch assembly. Can you unlock the door with the inside door lock linkage? If there is a knob at the top of the inside door panel that goes up and down when the door lock is activated, use that to unlock the door and then open the outside latch, then open the latch on the side of the door.