Question

How does south America's location over the equator affect its overall climate

Answer 1

The majority of South America lies south of the Equator, which is why it is called South America. The equator line winds (Coriolis effect), which blow daily from east to west, have a significant effect on the climate. These winds carry ocean moisture into the lowlands of the Amazon river. The western mountains (Andes Mountains) obstruct moisture escape and it spins counter-clockwise to the south and east. This moisture is absorbed by the frigid south pole winds, resulting in an abundance of rain in the tropical cyclone.
South America's triangle form is ideal for rains because it permits polar winds (from west to east) to blow in, sometimes up to the equator line or near to it, carrying more south ocean moisture into the continent and generating showers.
Another significant component affecting climate is the South Atlantic high pressure, although that is a separate subject.