Checking for fan freewheeling needs to be done with the engine at operating temperature. When you shut the engine down, the fan should stop abruptly or within 1-2 revolutions. If it coasts down or freewheels, the clutch is bad. You'll probably also see oil/dirt on the front face of it.

As for testing the Aux fans through the CCU, if you performed the test correctly, the fans should run. Have you checked to see if there's a failed fuse for the fans? One of the 210 guys will have to help you further with that...

__________________
Current stable:
1995 E320 157K (Nancy)
1983 500SL 125K (SLoL)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Gone and wanting to forget:
1985 524TD 167K (TotalDumpster™) [Definitely NOT a Benz]