This is my third Latitude 7480. The first one was not turning on. The second one, after loading all the things on it and get it going, I turned it off. Went home, never turned it on again until I went back to computer support. They did something with the battery and it was working fine. The replacement of the second one came in and now the thrid one has the problem that you describe. The fan never stops working and especially when it's connected to the charger the fan is so damm noisy!
I updated the BIOS on a couple more 7480's. The fan fires up initially, but stops after a reboot. It seems that the other 7480's in question are actually experiencing this because of CPU usage, and not due to the BIOS rev.
If your 7480's fan is running non-stop, see if it continues while running the Dell Diagnostics and/or booting Windows into Safe Mode.
I have used Dell Diagnostics, also booted in Windows Safe Mode. The fan is still running loud :-(
The latest chipset drivers are already installed, included the videocard, sound, bluetooth & wifi, lan drivers.
Any resolution to this issue? I got a user that also has a latitude 7480 that has a fan that constantly runs, even tried to go into the additional power settings to adjust the cooling in the System Cooling policy to passive and the fan is still running. Will there be a new BIOS update any time soon?