Back Door.
 

I just bought a 1982 300 TDT wagon. Yesterday the locks all worked, but not today. The Hatch will not lock or unlock with the key. I unlocked it from the inside and the door will still not open. Any suggestions?

Sounds like the linkage may have come apart inside the hatch - I seem to recall this happening on our 1984 300TDt. You'll need to climb over the back seat and remove the latch from the inside to gain access to the locking mechanism and see where it came apart.

Does it feel like anything is happening/connected when you press the button from the outside or pull the latch from the inside?

thanks, i got the lock open, its a little quirky at times though,but as of now is working ok