What is your engine temp? It should be around 80 degree C. It should
maintain that regardless of any traffic condition, city or highway. If not,
then your thermostat is bad.

As for your aux fan, I think you have a thermoswitch problem... on top of
your engine in the front, there are a couple of thermoswitch by the
thermostat... change them all as they probably are all original. Do this
only when engine is cold.