How do you know if cooling fan relay is bad in a ford windstar?

To determine if the cooling fan relay is bad in a Ford Windstar, you can start by checking if the cooling fans activate when the engine reaches operating temperature. If the fans do not turn on, inspect the relay by swapping it with a similar relay in the fuse box to see if the fans operate. Additionally, you can use a multimeter to test for continuity across the relay terminals when it should be activated. If the relay fails these tests, it may need to be replaced.