Poweredge RAID 6i Controller power connector

Hi - I have a very old Dell Poweredge RAID 6i internal card in a T7500 server. On the top edge is a flat 4 pin connector with just 2 wires, a black and red one. The problem is it can go either way round. It connects to the motherboard where it says AUX_LED. Both ends of the lead are the same and are like the old audio leads on early CD/DVD drives. Black and about 10mm x 2mm with 4 pins in a row.  I guess it is a power supply of some sort, but I don't know which way round it should be connected. The two wires are on one end of the 4 pins.