Problem with the temp sensor.
== == Cooling fans are designed to start at 235 degrees
Main Fan 228*F Aux Fan 235*F
The cooling fan comes on when the engine reaches a certain temperature and is controlled by a sensor switch that kicks the fan on when the temperature reaches the preset temp.
Should start the auxilliary cooling fan
engine cooling fan should not do this - bad temp sensor likely
Check the temperature at the radiator when hot Cooling fan is designed to come on only when:A/C Compressor is on (either during cooling or defrosting) orwhen coolant temperature exceeds 235 degrees Fahrenheit
The fan is controlled by a temperature sending unit. They usually start the fan up between 180 and 200 degrees.
Check water pump repl. thermosat repl coolant repl. water temp. switch swap coolant fan Problem solved when repl. cooling fan relay it had an Intermitent problem. sometimes the electric cooling fan would come on then it would not when temp. was at it peak no fan after repl the relay it worked properly.
In my experience, most electric fans come on when the coolant temp sensor signals the computer to start cooling when the car has run up to temperature. Another factor is the fan relay/fan relay control module. I think just the fan clutch type start up with the engine.
it usually turns on around 200 degrees
First check that the fan does work. Unplug at the fan and jump the wire to see if the fan works. If yes, then change the fan temp sensor or check the wiring to the sensor. If the fan does not come on when you jump the wire, then have the fan replaced.