Customer states they have owned the vehicle since new and the cooling fan did not come on until warmer days. It was about 65 today and the AC is cooling great, low speed fan was coming on and can not find any information as to when the fan is controlled and what temp it is supposed to turn on at. The transducer appears to be running very close to actual system pressure. Any help would be greatly appreciated.
So the customer is saying they don't think the fan should be on?? Im a bit confused on the customer concern. Id check ECT, CHT,AAT,IAT,and the A/C Evaporator temp sensor data pid.
There has been many issues with these. One being the AC pressure sensor. You stated it reads correctly. The other is a fan operation complaint after cooling system repairs. Aftermarket parts store thermostats do not work on these newer trucks. Has any cooling system work been done?
What tool are you using to pull codes? I have seen several newer vehicles turn on the fans due to a fault. Usually its the high speed fans though, but you sure know when one pulls on the drive! Maybe the fan is making more noise than the customer is used to due to a noisy/failing bearing or something? Hard to say what's excessive when it's not your everyday driver.
What describe indicates normal correct operation. Why is there a concern?
If memory serves correct the cooling fans on these trucks are PWM. They usually start turning on around 200 degrees F or so. IN the scan tool data you should be able to see the PWM control command around those temperatures with A/C off. Normally I see them kick on around 205 degrees. With A/C on the fans should be on till A/C is off or if the engine has reached the 200 something temps to have
I have seen a run on excessive pressure in the ac system causing this, Check the ACP pid. If the pressure is up with the AC off the fan will come on. unplug the pressure switch and if it goes off, compare the pressure with a mechanical gauge, There may be a blockage in the system