Rear blower motor
 

Did all X's come with a rear blower motor?

How is the motor controlled?

i think if the car had the rear A/C, then it had the blower... maybe not... :)

Ditto...if your X5 has the rear blower, then it came equipped with option S533A (Air conditioning, rear)...and the rear vent should have icons & a control knob/dial to turn the blower off/on.

If you don't have the rear AC option, then you will just have a dial on the left that opens/closes the vent ... and/or a stratified air dial on the right that allows the rear passengers to temper the air cooler/warmer. There are 3 different part nbrs for this rear vent which probably go with the type of HVAC system installed (standard-IHKR/auto-IHKA/auto-IHKA with rear AC)