Well, have you checked all fuses and the relay?
Here is the system
http://www.bimmerboard.com/forums/posts/145262/
no blower fan?
http://www.bmwe34.net/e34main/mainte...ical/sword.htm
wiring diagrams where you find the fuses and relays
http://shark.armchair.mb.ca/~dave/BMW/e34/