Electric fan runs all the time

I don't believe you are getting an accurate engine temp. Get an infra red gun to test. Test temp sender as well as the gauge. New doesn't always mean it works.
To constantly run at 145° something can't be right . Unless you are living in 30° weather, it has to be higher.
Fans are intended to be effective at speeds below 40-45 mph. After that, they become a restrction for airflow.
The natural force of the air at speeds above that exceed the fans ability to flow any more air.
So number one is to accurately verify your temps.
Before and after thethermostat. Top and bottom tanks and the core itself.
Pressure test cap. Should be 15-16 lbs. Thermostat 180-195 ° Coolant 50/50% Distilled water to coolant ratio.



Here is a very simplet test to do first. Disconnect power to the fan and run the engine. Now what does the temp gauge say ?