Dear xychrmsme,
I'm not expert, but I suspect several things.
1. The thermoswitch on the engine is not working properly.
2. The extra fan's resistor not working because usually corroded.
3. The thermostat is installed backward, so the coolant flow is not normal.
These are things that can make engine overheating. Living in the Tropics, overheating is one common problem for me.
Hope you find the problem.
Bye