MSD = means May Suddenly Die, and my guess is that yours died...
Reverse the diagrams and you are back to stock configuration... unless someone cut up the wiring harness, which isn't uncommon.
MSD wiring:
OR
Diagrams courtesy of Tmoss & Stang&2birds
Ignition switch wiring
Fuel, alternator, A/C and ignition wiring
See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring http://www.veryuseful.com/mustang/tech/engine/ Everyone should bookmark this site.