How do you know if the evaporator core is working?

To determine if the evaporator core is working, check for cool air blowing from the vehicle's vents when the air conditioning is on. Additionally, inspect for any signs of moisture or leaks around the evaporator core area, as this can indicate a malfunction. You can also feel the temperature of the hoses connected to the evaporator; one should be cooler than the other if the core is functioning correctly. Lastly, a musty odor or fogging inside the vehicle can signal issues with the evaporator core.