Method for operating a vehicle cooling system

A vehicle cooling system, comprising:

• a main cooling path and a secondary cooling path branching off upstream in the main cooling path;
• a main cooling unit for generating a main cooling air flow passing through a first heat exchanger arrangement being associated with the main cooling path and a secondary cooling unit, located upstream in the main cooling path, for generating a secondary cooling air flow passing through a second heat exchanger arrangement being associated with the secondary cooling path;
• a first operating mode, both the main cooling unit and the secondary cooling unit are operated by a control unit in order to generate mutually independent cooling air flows;
• and
• a second operating mode, the main cooling unit is operated via the control unit and the secondary cooling unit is one of a stationary or an idle operating state so that, due to the pressure conditions prevailing upstream in the main cooling air flow, a passive secondary cooling air flow passing through the second heat exchanger arrangement is produced.