There's a crank sensor underneath the module. You have to remove the module to replace it so I always replace them as a set. It's kinda hard to get out so try not to break it, or you'll have a time digging it out. It has an o-ring holding it and over the years it gets hard and doesn't want to let go.

President
East Tennessee Fiero Club
Robert Finley
RobsFieros@comcast.net