In my opinion the locks are purely coincedience or just noticed as you are being more observant right now..The locks are vacuum controlled and you may just be running out of vacuum since it has not been running. I am unaware if the 85 300TD has a electric vacuum pump for central locking system like my 87 300d if not you stored supply of vacuum may be out from you pressing the brake by habit while trying to get ignition to turn or some other leaks. The drivers lock is mechanically connected to the door tumbler so it will move with the key no matter what.

Arlo

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W211 E550
HVAC/R Certified Technician