I think I figured it out but was curious about any responses. I looked at a handfull of diagrams and there's differences in them. The car I'm working on has a 4 way connector for vacuum (second photo) and another diagram has a 3 way connector (first photo, "G"). The line that's plugging into "H", on this engine, comes from the other side. So, I don't believe I need a 4 way connector, but just a 3 way. The diagram you're showing, shows a 3 way (#21) connector. I know, this engine has been rebuilt so possible for things to have changed from original.
So, I plugged the 4th hose and put it back together. BTW, changing an AOS on a 996 without dropping the motor is a nightmare. Sticking phones in tight places to find the bolts and using mirrors to help out. Never again.
Thanks for the response.
