Harnesses which consist of six or seven sets of wires lead from the power supply. Look for the two connectors which have six wires each. There should be labels on the side P8 and P9. The power is supplied to the motherboard through these wires. These connectors will attach to the motherboard in only one direction.
If you are having trouble attaching a connector, it is probably on backwards.
Make sure the ribbed side of the P8 and P9 connectors face the power supply connector on the motherboard. Each connector (P8 and P9) have 6-pins.
Connect these pins to the 12-pin connector on the motherboard. Make sure that the
four black wires are located in the middle of the 12-pin connector.
BE SURE AND CHECK TO MAKE SURE THAT THE PINS ARE CONNECTED CORRECTLY. YOU CAN EASILY FRY YOUR MOTHERBOARD.