Enging Electric cooling fan

What is your question?

My 2000 Audi A6 2.7 has a radiator electric fan in front of the radiator that works fine. Then their is the belt operated fan. Their also in the same area to the left of the drive belt fan their is a nother electric engine cooling fan, which does'nt seem to work. What would cause this fan not to work if it's not the cooling fans motor?