inside the door panel
A motor from a 1991 Oldsmobile will fit into a 1996 Oldsmobile Delta 88. The motor mounts will need to be changed.
In the engine compartment. Center of the firewall behind the engine.
have someone check the wiring of the window control panel, if its not that, its your window motor, for a '90 a used motor from a junk yard probably wouldn't be more than 30 bucks
fuse #5 on the relay panel on firewall left and above blower motor.
break the window
Behind the driver, under the frame.
Directly behind the engine, on the middle of the firewall.
Check fuses Check for loose connection in fuse block
Hemmings Motor News.com
under the hood on the fire wall.
They are generally located close to or near by the blower motor.
in my 89 Oldsmobile delta 88 , the heater motor was directly under the center of the windshield under the hood. black circular thing.