Does it refer to the black and white plugs at the bottom?? 'cause from what I remember, mine had two plugs going into it, the hose bit that connects to the black circle in the middle, and something that connected towards the right side (looking at that pic ^^^^^) but it connected to something that looked more like the black plug at the bottom of that pic ^^^ it's a '91 Digi, so would that make it a single plug??