Hi,
I'm in Sunny but Rainy FL and it's raining. My windows had been moving slowly when a/c is on. Now the driver's side is stuck open @ 3in. Its "reving" but will not go up all the way. It goes down but had to pull it to get to 3in open. It's making a grinding? sound. Is it a fuse?

 

'Sounds like the regulator is shot to me. You will likely have to replace the whole unit.

 

Check your window gasket/slide guide. A common problem spot, it can shift, causing the window to get in a bind. I had to roll down the window, pull mine out, clean it, and put it back in with silicone to try keeping it from shifting. Wasn't a permanent fix, 4 years and mine is getting troublesome again. That and some graphite lubricant helped the window move more smoothly though.
Sounds like the regulator is still trying to work, so it may not be shot yet. Usually when regulator is shot, window is stuck in one spot, in my experience anyway...
Pretty sure fuse is fine.

 

That may, or have been the cause but if it's grinding, it ain't gonna last from my experience. There isn't usually a built in clutch in window regulators, or within their motors, and just a simple set of direct drive gears that drive the window mechanism... sometimes made out of plastic.
The only other thing I can think of is that a motor rivet is coming loose from the regulator assem causing gear misalignment when under a heavy load, like when trying to fight friction and gravity (trying to raise the window.) Down is of course much easier for a window regulator.