2016 Ford F150 5.0l cooling fans on high

So this truck was towed in for coolant loss and no power. When i started it up ran like crap, check engine light, and message in dash for cylinder head temperature protection. Temp gauge pegged high, and this was after truck sat in our lot for 24hrs through a heavy rain storm. Any way scanned, had codes for engine over revved, engine over heating, cylinder head temperature protection and one for the cylinder head temperature sensor. Did a visual for leaks, damage, etc. Pretty sure they got stuck and over revved it trying to get it out and it overheated. Its a mill truck always in woods. Looked up codes, did some diag from Identifix. When i cleared all the codes, truck started and ran fine, temp gauge went back to zero. Ended up replacing the cylinder head temp sensor, it stayed pegged at 240F. Replaced thermostat, washed all the mud out of the rad and condenser as well as replaced the coolant pressure cap, it wouldn't hold any pressure when tested. Also replaced the exhaust pipe between the 2 cats under the transmission pan, they hit something and pinched it shut causing to much back pressure on drivers side. Road tested, everything good. the company sent the driver to get the truck this morning, they went back to work. This afternoon about 3, they come back with the fans stuck on high. Said they came on a couple hours after they picked the truck up and wouldn't shut off. Scanned, had a code for coolant over temp, gauge read in middle at operating temp, and scan tool said 200F, i'm in Canada, we use celsius, wasn't sure of the conversion, but i thought that was around operating temp. Anyway, looked up code, and it basically said check cylinder head sensor, thermostat, check for plugged or blocked rad, etc. Then it said to check operation of the shutters in front of the rad. Found them to be closed when the truck is running and i was unable to cycle them open, but if i turned the truck off they opened. So i unplugged the motor for them while they were open, so they could get airflow and go back to work, until they could book it in next week. They took the truck, but came back at 5 with the fans on high again. They said the fans didn't kick on going down the highway but a few mins after they stopped they said they came on and wouldn't shut off again, so they left the truck with us.
Anyone with an idea, i watched a couple vids that said check the A/C high side sensor, but the coolant over temp code is making think it might be something else.
Any help is appreciated.