The fan is controlled by a solenoid in the power steering pump. When there is a demand for cooler air the solenoid allows maximum pressure to the fan to turn it harder and faster, like in traffic or stop lights. Check your fluid in the power steering reservoir and also observe the fan speed. If it is not working or going faster, jump the pins E and FB and you should see the fan spin faster. if that does not happen there is a problem with either the solenoid or wiring.