when driving highway or local and when I bring to ford of course problem not there

Trying to take nut off the end of the strut. I clamped the end plate in a vise and turned the nut with a socket and the cylinder turns in the strut. I try to hold the cylinder with a pipe wrench but it won't grab. I was not sure I was doing it right so I stopped before I messed it up more. How do you get the nut off? The numbers on the strut are T407HFoMoCo USA,
BB53 18K001, 111031A and a very big DB

do I need to remove grill fasia/bumper to be able to remove the radiator

I recently installed a new battery in my 2012 Ford Explorer. The new battery has been in my vehicle for over a week now and the car has been running great. Well today my CHECK CHARGING SYSTEM warning light came on and I need to know what this means