central door lock/unlock

[Mike Arman]

Car is 86 5Ks, central locking operates from driver's door only (later
models work on both front doors, this one is driver's door only).

Problem is this: When locking the car, the knobs move down and the vacuum
door-locking motor under the rear seat stops running in a few seconds.
However, when unlocking the car, even though the knobs move up promptly and
the car unlocks nicely, the motor runs for at least two minutes.

How long should the motor run for each up cycle and each down cycle? Is it
also possible that I've never noticed the motor running because usually,
after I start the engine, I can't hear the vacuum motor running anyway, and
it is working normally?

Any ideas as to where to look for this problem (if it even is a problem)?

Best Regards,

Mike Arman