2003 Jag S-type engine cooling fan comes on and stays on

the air con fan comes on with the air con switch. the engine cooling fan comes on when the engine temp. censer reaches operation temp. most times the air through the radiator when driving is enough to keep the censer cool and the fan not working if you stop at lights for any length of time it will come on.

change the thermostat, sounds like it could stuck open and wont allow the engine reach operating temp, also test the constant control relay module located to the right of the battery as your facing the front of the car, also test coolant temp switch it might be defective and producing a high voltage that would cause the fans to constantly operate no matter the temp. Hope this helps

If the check engine light is not on, I would want to check the computer with a scanner to see what the temp sensor is telling the computer the coolant temp is. The problem could be in the computer or the fan relay.

Is the engine actually cooling off? If the temp switch isn't seeing a drop in temperature, it will keep the fan running.

You may have a locked up compressor. The fan only comes on when temp reaches 225 on high speed. Your low speed fan operation is controlled by the resistor that is between the two fans at the top. The connector usually melts and you will need to get two heavy duty female spade connectors to repair it.

You probably need to bleed the cooling system properly.

Open the cooling system bleeder screws.

Slowly fill the cooling system with a 50/50 coolant mixture until coolant runs freely out of bleeder screws.
Close the cooling system bleeder screws
Install the coolant pressure cap
Start the engine.
Run the engine at 2,000 - 2,500 RPM until the engine reaches normal operating temperature. (midway on gauge)
Allow the engine to idle for 3 minutes.
Shut the engine off.
Allow the engine to completely cool.
Top off the coolant as necessary.
Run engine again at 2000 - 2500 RPM until the engine reaches normal operating temperature.
Allow engine to idle until cooling fans come on. It should come on with the gauge about 3/4 of the way to red. - if it gets to where is touches the red, shut down immediately.
When the fan comes on, put your hand behind the fan and observe the temperature of the air coming from the fan. It should feel hot. If it is blowing cold air, the coolant is not circulating through the radiator like it should. This could be caused by lots of things including an improper/defective thermostat, corroded water pump impeller, or a blown head gasket.

time to replace eather temperture sending unit to the fan or the fan itself do not keep running the engine hot you could camage the head Gasket get this fixwd soon

There is nothing to worry about. The cooling fans do not operate by engine speed, but rather engine temp. If the fans stopped working, then there would be a problem with either the cooling fan relays or the temp sensor which operates the fans. Otherwise, you are fine.

You say it's overheating, more info needed such as:
Is the engine temp gauge showing that it's overheating?
Is it actually 'boiling over' and losing coolant?
If it's running hot, but not losing coolant, check to see it the cooling fan is operating when the engine temp rises. You may have a bad cooling fan switch that is not signaling the fan to go on to lower the engine temp.
It could be a stuck (closed) thermostat that is preventing proper circulation of coolant after the car reaches operating temp.

Hey there..my name is Keith..and i can think of 2 possibilities..1 is the fan motor needs to be replaced or 2...the temp sensor needs replacing..thats what tells the fan to turn on and off..i hope this helps