2007 379 fan runs all the time

[MPDiagnostics]

Check fan drive state in Insite. What’s it say when is on? Air Conditioning? Or Coolant Temp? Or anything else?

Also even though A/c is off - the fan switches on the A/C system still can cause the fan to sometimes come on if there is a fault with them. It could be wiring or switch itself. But you have to confirm the fan state first which will tell you the reason why the fan was turned on.

Maybe even bad fan solenoid failing at higher temps around the engine?

Just some ideas