All x5's were may 99MY or higher, they are all equipped with a Final Stage Unit controled by a control module, and this control unit is controled by pulse width from the Engine Control Unit. There were several re-calls on early bmws for these catching on fire. On every startup, The DME checks the operation of the Aux fan by sending a signal to the Control unit to turn the fan on momentarily. It then reverses the signal line into a listening line to measure the amount of amperage being generated by the fan as its moving. The aux fan should operate at 10hz when the temperature is 120°C

so, when my temp is at 119, I am still OK? Is there a way to trigger the fan for a test mode, or somehow make it run just to see if it works or not? I do not have any errors logged into the OBD II things, nor anything shows up in cluster... but I have a suspicion that the fan is just sitting there, collecting dust and is not willing to work... During a start of the engine, you say that it should move slightly? I am going to try it tonight... If it moves, then it is good?

Geee, so much electronics in these cars, I would not be suprised if the next wave will be making viruses for the car computers:

if you are on the 66th mile of the connector road 666 (as determined by the Nav), at 6 minutes past 6 in the morning, on Friday, the 13th, your radio will automatically turn to the 130 MHz frequency and the car will magically give you a "Blue Screen of Death" with sound of the Grand Finale Laugh of Michael Jackson's Thriller!!! Ahr-HA-HA-HA-HA!!!!! Arrr-HA-HA-Ha-ha!!!!