1989 BMW 325i blower/window motor help?

Yes, the 2 systems are distinct from each other.

The blower is powered by fuse#20 (30 amps). And fuse#17 (30 amps)

powers the power windows. Additionally, the power windows are also controlled by a circuit breaker (this is the switch/button on the middle of the dashboard, slightly above the center console,with no name).

And yes there are unloader/dumping relays that in turn give power to the fuses already mentioned. K5 (on top/beside fuses 16 & 17) powers fuses 16 & 17, and K7 (on top/beside fuses 24, 25 & 26) powers fuses 19 & 20.

The unloader relays in turn are connected directly to the battery.

If you think this is complex, you have not seen anything yet. The newer models are so much more complex than this '89 car of yours.

EDIT:

If the relays, fuses and circuit breaker are all OK, then you may have a bad AC blower switch,or a bad blower motor;

a bad connection to the doors (where the cables connect to the body on the A-frame), bad power window switches, or bad window motors.

First go under the hood and check all the 25/30 amp fuses, if it has a 30 put in a 25 its a little known drive ability campaign BMW had years ago. The blower motor ones are usually bottom left corner. Drawing a blank where the window breaker switch is. In the car there is a 1/2 X 2 1/2 black button with nothing written on or around it to identify what it is. This button needs to be checked by pushing it back in if its been thrown. The two systems are not directly related and are not on any one fuse or relay. I think you have 2 problems. A lot of the times when people first get a BMW of your year they accidentally hit that window switch. As to the fan, ask again if the fuse is not the problem.