Why doesn't the fan turn on when the car's AC is turned on?

[VonHaven]

There are several reasons why the fan doesn't turn on when the car's AC is activated: 1. The coolant temperature hasn't reached the required level: Most modern car radiator fans operate with electronic temperature control, meaning the fan will only start spinning normally when the engine coolant reaches the specified temperature. If the temperature is too low, the radiator fan won't operate. Therefore, if the radiator fan isn't working, the first thing to check is whether the coolant temperature meets the requirement. 2. Faulty relay: If the coolant temperature is adequate but the radiator fan still doesn't work, the issue might lie with the fan relay. A malfunctioning relay can prevent the radiator fan from operating. 3. Problem with the temperature control switch: Sometimes, the temperature control switch can develop faults, which may affect the operation of the radiator fan. Hence, it's also important to inspect this component.