Ford Repair: Starter on Aerostar, ford aerostar, voltage signal

Question
I have a 93 Ford Aerostar w/ a 3.0 engine.  The starter was not working (or so I thought).  I checked all wiring to make sure they had a clean connection.  Still didn't work.  I replaced the starter.  Still didn't work.  I replaced the starter switch on fender near battery.  Still didn't work.  I am stumped.  I know the van will still works.  What else can I do to troubleshoot...then fix...the problem?

Answer
Hello and thanks for the question...I'll try to help.
At the solenoid on the fender....check to make sure you have the wires correctly placed and then check to see if you are getting a voltage signal at the trigger wire at the solenoid.
Hope this helps,
Erik