6nz fan won't shut off

I had the same problem with the awful 6nz here. And people think these motors are so great.
Anyway, find a hot wire run it through the dash to a toggle switch, run the other side of the toggle connection to the hot side of that solenoid. That's what I did.

 

Has nothing to do with the 6nz that fan hub could care less what motor its on are you sure the fan hubs good ?

 

If it sat a long time the clutch is probably stuck together

 

Why is your solenoid leaking air if you just replaced it?

I don't know which type of fan clutch you have, but you may have the type that requires air to not turn. Then if you were to lose air for some reason the fan will lock up and keep the truck cool, like if your solenoid went bad and stopped supplying air.

Put shop air directly to the fan clutch and see if it releases.