Volkswagen Jetta radiator fan runs continuously after engine shut off, draining battery on Volkswagen Jetta

Some Volkswagen Jetta owners report experiencing issues with the radiator fan running continuously after the engine is shut off, which can lead to battery drainage. This persistent operation may be attributed to several factors, including exhaust gas post-treatment processes like particulate filter regeneration, active brake cooling after descents, and the dissipation of engine heat following high load situations, such as when towing. Additionally, owners may encounter problems due to a dirty radiator, a faulty electronic control unit, defective temperature sensors, a bad fan relay, short circuits, or faulty freon pressure. In some instances, the cooling fans may operate even when the vehicle is cold and continue running for about 15 minutes after the engine has been turned off. While this after-running is often intentional to prevent excessive engine compartment temperatures, it can also signal potential issues with temperature sensors or relays that may require inspection and replacement.