No, it spins at all times, but the coupling % is what changes. Low coupling is like 20%, high is maybe 60-70%. A heavy duty clutch will couple at maybe 90%.

But fan clutch does not turn off the heater.

 

No just thought it wouldn't allow the engine to get warm enough. Ok, I'll run it around town tomorrow and see if the coolant was the issue. If not I'll change the stat. Thanks for the help as usual guys.

 

The engine fan has nothing to do with the engine warming up.
The engine fan only pulls air past the radiator to cool the engine when you are not moving or in slow speed driving.
if there is no hot coolant in the radiator to be cooled off the engine fan does nothing, the engine warms up from the inside out.