Cooling fan acts normal when the car idles, turns on fan at 95-96c. The problem is that the fan kicks in (high speed) after few minutes of driving (also the temp needle drops to the starting position and doesn’t come up). So initially i tought the problem was the ect sensor but to no avail. Relays and fuses are fine.
What, exactly, did you do with the ect sensor? Replace it and still a problem? Confirm it works? And how did you do that?
If this is a 2.0 liter 4, it has a cylinder head temp sensor that I think actually is used for fan control. Do you have a scanner that can read cylinder head temp?
Yes, changed the sensor. I can confirm that it works, watched the temp rise via delphi diagnostic (that’s how i knew it turned on at 95-96). Also yes i noticed in live feed cylinder head temp but the temp rised normally along with ect. Forgot to mention there are no faults. Originally car came in shop because it was going into limp mode and also because of the fan. Now i managed to solve the limp problem (the contacts were bad inside of the dashboard).
So the engine is at operating temp… 95-96C at low fan, what happens to the temperature readings, cylinder head and ECT when the fan kicks to high? Reading from the scanner… is the ECT reading 95-96? Does the gauge drop to start even though the ECT reading 95-96? And Cyl head temp reads what during that event?
I need to check tommorow just to be sure but i think that the reading of both temps were stuck at 70c when fan kicks in.
Those fans are usually controlled by relays. Are you able to measure the control voltage that turns the high speed fan relay on and off? To properly diagnose this problem you’ll need to figure out if the problem is a faulty control signal to the relay, or the relay itself is faulty. Are you certain there are no diagnostic codes stored in the computer memory, and no warning lights on the dashboard? In certain abnormal engine operation situations the powertrain computer will turn the engine cooling fans to max, overriding the normal temperature control, in an attempt to prevent engine damage.
That seems like a PCM problem to me. I don’t normally go to that but the car is older and the results sure seem consistant with that.
Maybe because of my recent PCM replacement on my '13 Mustang…