Is there a fuseable link that controls radio, seatbelts, and door locks.
I have a 1990 Maxima and the door locks, auto seatbelts don't work with the key off. Also, radio does not hold memory.

 

I'll say it's related to the battery.

 

Update:

New alternator and battery.
Problem is there is no power to interior when car is not running. If car is off, and ignition is on or in acc position, there is no power to radio, locks window, seat belts, ...
Is there a relay, or is it the ignition switch. When the car is running, everthing works fine.

 

It could be either one. I would check all my relays under the hood. From there I would check the wiring to the ignition. One of the two you'll find your answer. Something is canceling out everything. Hopefully its a relay.