BMW Repair: E46 Radiator Fan Stuck ON, radiator fan, thermister

Question
My radiator fan on '99 E46 328i Sadan is stuck on at full duty cycle. I have to unplug it when the car is turned off so not to drain the battery. Is there a relay possibly stuck open, a faulty thermister thinking the engine is hot, etc.? Unlike my '03 X5, the 328i fan never stayed on to cool the engine after I pulled the key before.

Answer
Trey the final stage controller on the fan is shorted internally. Replace the entire fan assembly. Common problem with this model and year. You are not alone. Fan is a little expensive though. Good you noticed or you'd have had a dead battery on your hands. Thanks. Let me know how it goes.
-Evan