I am not a mechanic and don't have many tools. I was told the vacuum modulator needed to be replaced on my 1990 subaru loyale turbo and that it was easy to do myself. I am hoping to get some info on locating the modulator (do I get to it from under the hood or under the car? Passenger side or driver side etc.. ) Thank you.

If I remember correctly the turbo loyales after 1987 used the 4eat transmission that does not use a vacuum modulator. The function of the modulator is done by the transmission control module. Who told you that it needed changed and what are the symptoms?