MSD 8987 Start and Step trouble wont start .

Just tried hooking up a new MSD start and step to my nitrous setup which consists of a N.E progressive controller a MSD window switch which worked good so i decided to add a start and step . I carefully hooked it all up per instructions now i have a no start condition , anyone else have this problem . I checked and rechecked the wiring 10 times and it all seems right . any ideas ?