Coolant fan never turns off

There are a couple of ways that the fans will stay on high all the time.

The first is that the temperature sensor is not accurate, and it is telling the PCM that the temperature is high.

Next is the engine temperature is actually high. So, let's make sure the engine is not overheating. However, if they start running when the engine is cold then this is not the issue.

Also, the fans can be stuck on high, so we need to check the voltage at the fan to find out if they are being commanded to high or are stuck on high. This is less likely.

The most likely cause is the temperature sensor is faulty or the PCM is commanding them on.

https://www.2carpros.com/articles/how-to-check-wiring

Because of this we need to check the voltage on each of the 4 wires going to the fan when the engine is on, and the fan is turned off.

Let me know what you find with this, and we can go from there.

Then we are going to have to test the coolant temperature sensor.