How can I test the 12v power connector on my motherboard?

The ATX 12v 4-pin cable that leads to my motherboard didnt read any voltage when i tested it and i tried every combination of switching the multimeters leads to different pins. When the two prongs from the multimeter were in the connector and touched each other it sparked however still no reading. I am positive i have the settings right and the right leads in the right slots on the multimeter. Is this power connection vital and if so what am i doing wrong?