my old Plymouth's fans (it had Dual fans) would come on at 220F for the Low Speed fan, and 230F for the High Speed fan. the gauge would usually be slightly above the first thin hash mark under normal operation (the needle would get near the middle mark, then drop as the thermostat opened), and would only move to the halfway mark if it had been sitting idling for a long time (about that time, the Low speed fan would come on to cool down the cooling system)