2002 Chevy Trailblazer Cooling fan Clutch issue.

Hey all. Last night when I was on my way to work my Trailblazer sounded like the fan clutch was stuck on the cooling fan. Today my wife and I were running errands and when we were on our way home the truck threw a check engine light. I found out that the clutch is not a simple mechanical clutch but an electro-viscous clutch controlled by the PCM. Does anyone know you these work? Is electricity applied to stiffen up the fluid or is it the opposite? I have not tried to move the fan with the truck being stone cold but with the truck off the fan is quite stiff to turn by hand. There is also a fuse for the fan and it is working. Please share any knowledge you may have. I'm also trying to find out what size the nut is on it, the largest wrench I have is 1-1/16" and it is not big enough.

Thanks
Mike

Some days I feel if I did not have bad luck I have no luck at all.:thumbsdown: