If the factory temp gauge doesnt work, does that mean the fans will not work correctly either?

What are simple checks to see why the Temp gauge is not working?

Can I change a setting in the datalogit to make the car run cooler?

 

No. The dash gauge and the coolant thermosensor are two different sensors.

First verify you have the right connector on the coolant sensor. The sensor is located under the oil filter pedestal near the oil pressure sender.

Yes. You can alter when the fans are turned on using the datalogit.