the fan speed ak power supply is managed via a resistor which sits in series with the motor.
0) As the indicator light goes on it appears the fuse is ok #10
1) disconnect cable from resistor (R) at the unit and feed 12 V directly to motor...see if it runs
(that should be possible per monkey style laying down on the pass. side)
2) if it runs check the resistor, it is a heavy Watt type I think with resistant wire on a ceramic body. It might be rotted or broken etc.
3) if not broken the switch might be the issue, as are old. Need to remove the kick board on pass side for access, well 3 cable comming /going there end up as 2 at the resistor BK & R, so you can check there. do not recap the switch internals but the indicator sits on a different Terminal on the swich W/BK thin cable.
(look at the elctrical diagrams page 40 & 11)
Matthias