Good luck and please yes keep us updated as to how it turns out!

Now, I kind of understand what is going on my radiator fans.
Coolant temperature sensor sends the temperature value to the ECM while coolant temperature sender
send the signal to the indicator on the driver'* pannel. So the indicator shows the right temperature of
the coolant because the coolant temperatuer sender is working fine.
However, due to the falure of the coolant temperature sensor that is supposed to give the value to ECM, the two radiator fans are not spinning.
So if my conclusion above is correct, I should replace the SENSOR not sender, am I right?
Thanks in advance for your comments.

You Sir are correct!

Now you got it. If you had a enhanced scanner you can get those values from the PCM and compare the two sensors.

Thanks a lot, I will replace the sensor and update the result.

I happened to see that the both fans are on when the temperature is above 200F.
The problem that I have now is that the fans are not on when the A/C is on.
However, A/C compresser pully is bypassed in my car since several month ago due to the failure.
I want to buy a used A/C compresser and reflush the A/C gas.
Does the not-working A/C system have to do with triggering the radiator fans?
I am sorry for not checking the high temperature response of the fans.
Thanks a lot
movingman

I mean, I turn on the A/C on the A/C button in the driver'* pannel but the cool air is not coming in because the A/C compresser is broken and it is bypassed.
The air is blown into the car but no cool air.
I just turn on the A/C switch on sometimes because I intentionally wanted to turn on the fans.
But now they are not responding to the A/C switch anymore.

So should I fix the A/C system for the fan to response to the A/C switch?
Thanks a lot.

It'* the AC controls that turn on the fan. You don't even need the compressor in the car.