quick wiring question for 1994 mazda rx7
 

Hi I just wanted to ask if anyone knows where this black plug with black/yellow stripe wire? It is located next to the ecu and blue plug. I just cant figure it out. If i ground it I hear a relay click when the car is off. I looked on service manual and it says it is for cooling but where does it connect to? any comments are appreciated. Here are some pictures.

https://www.nopistons.com/attachment...ine=1436253802

https://www.nopistons.com/attachment...ine=1436253802