What’s wrong with the low water temperature in Cherokee?

The engine cooling system is divided into a large cycle and a small cycle. The engine management computer switches between these two cycles. The hardware that controls these two cycles is the thermostat, and the software signal is input by the water temperature sensor. supply. The car has been in a low temperature state and there is a sound of running water in the engine compartment. It is suspected that it has been undergoing a large circulation. It may be that the thermostat or water temperature sensor is broken.