Sorry, I was not stating AC problem but actually the way to confirm the fan circuit is ok is to run AC, If fans come on with AC, then the fan circuit is ok.
The fans are controlled by 3 fuses, 3 relays, 2 fans and the PCM (computer)
If fans had worked then not, then worked, i doubt fan motor problem, nor relays problem.Doubt 3 relays failed all at same time. You did ECT sensor.
This leads me to one of a few things. Either the water circulation is not good and the water at the base of the ECT just is not hot enough to turn fans on ( even if hoses are hot) OR you could have a failed PCM. What concerns me is running hot at hwy speeds. This would be the same with air through radiator just like fans on as fans usually do not run at hwy speeds.
I am not there nor running tests but leads me to more of a coolant circultion problem rather then lack of fans. You can also put a large home fan in front of car to see if still overheats OR you can hose down radiator and if it still runs hot, you could have partially blocked radiator, a headgasket beginning to go bad, defective T stat, etc. just giving ideas and info on what to try. here is the wiring diagram you requested