What does the temperature gauge on the dash tell you about the temperature? Does it show normal or hot etc.
1.Have you checked the thermostat?
With a cold engine, remove radiator cap, start engine and allow to warm up. If thermostat opens then you will see 'flowing' of coolant in radiator neck. If the coolant doesn't seem to move, switch off the engine and feel the top and bottom radiator hoses. If the bottom hose feels colder than the top the thermostat hasn't opened. Be careful as the coolant expands when it heats up and may overflow the radiator neck.
2. If the thermostat is OK, the radiator fan is controlled by the ECU. There is an ECU coolant temperature sensor which tells the ECU to turn on the fan. Be aware that there are 2 coolant sensors close to each other. The one with only one wire is for the gauge and the other with 2 wires is for the ECU.