I'm Baaaack!!!
OK... here are some pics of a Vacuum Pump:
A part number for a pump from a 1995 Altima is 18955 - 1E800. This part number will be different for almost every different model but the prefix should be the same (18955) and should help a parts guy narrow down the search. I didn't price out a new one, you probably don't want to know. Go to You Wrench It, You Pull It, You Yank It, and get one for $10.
If you look at the bottom picture you will see I have three of the wires twisted together, these are all grounds. The single pink wire is hot. On the back side of the connector the pink wire turns into two white ones, so if you don't come away with the connector twist the two white wires together for your hot (12 volt in) and twist the remaining wires together for your ground.