I'm assuming you have push button, full climate control, as opposed to the rotary dials and A/c.
Gabor's circuit diagrams may be a help to you, but the fuses will probably be different, as yours is a Series 1 car.
download/file.php?id=9711
The Climate control thread in the Self Help files has the Xm climate control technical manual.
viewtopic.php?f=13&t=10604
Please see attached circuit diagram for the Climate Control system.
Tha fan is fed by +12v and Gnd and has a controller mounted directly onto the fan unit.
The variable fan speed is controlled by a pair of darlington transistors being variably dragged to Gnd via the Climate Control unit. The lower the resistance to Gnd, the faster the fan spins due to the transistors switching on more.
The lower the voltage on Pin-3 of the fan controller, the faster the motor spins, until the relay is switched on for full speed.
Full speed is switched by the relay closing, thus a direct shunt to Gnd is achieved. Try turning the fan speed to full, as that should use the relay, bypassing the transistors.
The transistors are known to fail and can either be replaced individually, or a replacement fan control PWB can be purchased.
This means you can test the fan by applying +12v and Gnd, then shunting the relay to Gnd.
It is known for the fuse holder to become overloaded and the fuse to no longer make proper contact, so cutting +12v to the Climate Control.
Also note there is a thermal overload switch built into the fan motor, which could cut supply to the motor itself. the thermal switch is on the +ve feed side of the motor, so applying power here and Gnd to the other side should make the fan operate at full speed.
Fuses and relays are in the below, linked, thread.
viewtopic.php?f=8&t=10268
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