Pretty simple electricals on that old guy. The aux fan should have its own fuse. The TWO inside fans will be separately fused also. There are separate fans for A/C and heating/ventilation, your problem there could be the heater fan or the switchover system.
The A/C and aux fan were special versions on those cars and they had separate fuse boxes (two fuses). The aux fan was turned on by a thermal switch on the receiver-drier or the 212 deg switch on the T-stat housing. To see if the fuse blows with the fan try jumping each switch (one at a time)to turn on the fan. If it blows with either switch then try it with the fan disconnected and the wires insulated.
The relays and fuses are on the passenger side firewall if I recall. Switch relays as the next step. After that you should inspect the harness to the fan and if none of that works get a bigger stick (bg).
[This message has been edited by stevebfl (edited 11-05-2000).]