Thisshould beanother easy one ...
Fan obviously works (runs with the A/C on) so no need to check fuses or relay. Replace the Engine Coolent Temp Sensor (ECTS), which is located on the driver''s side of the engine (two wire connector). Also, replace the connector itself, as they tend to fail over time. Make sure the new temp sensor does not have an exposed resin tip, as these tend to fail quickly. Use teflon tape on the new sensor threads.
About $10 to $15 usd for the sensor, and $25 for the connector. Good luck