How do i turn on my PSU without it connected to the motherboard

[chaparral]

I need to power on my PSU without it being connected to my motherboard so i can run my waterpump for leak testing ???

But i can't remember which pins i need to connect together on the 24pin PSU plug to power on the PSU....

 

[Will_3rd]

iirc it is the green and black one

 

[chaparral]

iirc it is the green and black one

Thanks