Climate blower motor
 

I have a 2004 C240. Replaced the climate blower and regulator. The first regulator was from manufacturer called URO. After installing it worked fine. I noticed a new feature that I did not have before, when turning the key off, the blower would stay on above for 30 seconds and then shut off. I read this is normal behavior. Well the next day upon starting the car, I found the blower was now stuck on high speed. This indicates to me my new regulator shorted out. I returned it and ordered a boschbunit. I put this in and everything operates fine except the blower no longer operates after I turn the key off. What gives? Is the boschbunit defective as well?

I think that the ac blower motor should always turn off when the ignition is turned off in your car. The only normal way the blower will operate with the ignition off is when the REST button is pushed "after" the key is removed from the ignition.
The behavior of the blower running after the key was turned off was probably due the obvious failure of the first replacement blower regulator. IMHO I think your car is fixed.

blower motor
 

Thank you for confirming this. The reason I asked, was that I seen previous threads where users said it was a feature where the blower would run for 30 seconds or so after car turned off to cool the heater core, etc.