The vehicle has electric cooling fans. You might hear the fans spinning at low speed during most everyday driving. The fans can turn off if no cooling is required. Under heavy vehicle loading, trailer towing, and/or high outside temperatures, or if you are operating the air conditioning system, the fans can change to high speed and you might hear an increase in fan noise. This is normal and indicates that the cooling system is functioning properly. The fans change to low speed when additional cooling is no longer required.