[LITTLE D]

fully charged battery and checked wire from battery to starter for flaws - none - then checked to see if i had juice to starter - yup got that. i looked at wiring diagram no "yellow" wire on that but there is one on the van that plugs onto the bottom of the starter/selenoid that tests negative on juice. is this my problem? if i squeeze the relay i can get starter to crank (i did replace the relay with a new starter relay). i am at wits end and don't know what to look at or do next. i was told that i didn't have a neutral safety switch (unless i had a manual transmission) but why if i call the parts store they list one? if i do/don't have one please verify which. and where the heck is this thing - drivers side? near bottom of engine? toward the grill or toward fire wall?