@zedonist, This was the drawing I came up with, this is using the standard BMW 3 pin temp switch. The standard temp switch has a normal speed and high speed switch, all this means is that the normal speed switches at a lower temp than the high speed. As you can see it was wired using the normal speed side of the switch. The relay which sits in line just before the fan was a generic relay with a switching current to match the fan.
Hope this makes sense?
Hope this makes sense?