Cooling fan does not turn off

Hey JP YUNGIN PEACOCK,

There are a few things that can cause this issue.

If you have A/C does it work?

Does your coolant temperature gauge read correctly?

For this fault to occur most likely the PCM is getting an incorrect reading from one of the sensors involved in the engine temp or A/C system.

Do you have access to a scanner?

Regards, Joe

My temperature gauge reads fine and my A/C works, just doesn’t blow cold. I think it just needs to be recharged with the A/C stuff, but my heat works fines. No, I don’t have a scanner myself but I can always go to AutoZone and put it on a scanner. can you give me better detail of what it could be?

Hey JP YUNGIN PEACOCK,

If there is excessive pressure in the A/C system or the pressure sensor is reading incorrectly then the compressor will not turn on and the cooling fan will run constantly to try and cool the condenser.

Check to see if you have any over fault codes for the A/C/ climate control?

Also, if you can get live data check the temperature readings from the climate control or A/C pressure sensor, the ambient air temperature, the coolant temperature and the evaporator temperature.

Let us know what these readings are.

If the A/C does not blow cold then it is not working it is just the heater fan blowing outside air. If you can take it to a shop to get the A/C pressures checked this will tell you if you have an actual pressure problem or a sensor issue.

They will check the low and high side pressures engine off and with the engine running A/C on.

Is your A/C always turned on? Does turning the A/C off stop the fan running?

Regards, Joe

No my A/C is usually off because it doesn’t blow cold air. the cooling fan doesn’t affect the car driving at all. it’s just always on until I shut my car off. could it be the cooling fan itself could that be the issue?

Hey JP YUNGIN PEACOCK,

The cooling fan itself in unlikely to be the issue as it is does not have a constant supply, this means even if it does short internally it will not have a feed unless the fan controller supplies it.

I think we are looking at a potential over pressure/sensor issue with the A/C if you can get codes/data from my previous question that would be great.

Regards, Joe

Hi JP, if the fans come on when the key is on then I would suspect a bad engine coolant temperature sensor. That will be the one used for the engine control module. The sensor is located on the thermostat housing. Attached image below. Remove the connector and also inspect the pins for corrosion. Most likely the sensor is close to open circuited or will ohm out in the mega ohms reading.

I would recommend replacing the sensor and recheck the operation of the fans.