IF the starter does not engage it is:

RCM
Clutch interlock switch
Pulse module
Bad starter (it's never a bad starter)

One thing you can do, yank the pulse module, pry the cover off, press on the starter relay - if the starter does not engage, the starter itself is bad. PERIOD.
Be careful, pressing that relay bypasses EVERYTHING. The starter will engage even with key off if you press on that relay.