97 T-Bird - Starter Switch/Wiring Issue?

97 LX 3.8L V-6. Very well maintained car. She said it cranked a bit slowly on her last drive. Now wont crank at all, or even click the solenoid. Brand new battery. Voltage is good. I jumped battery to start terminal on solenoid, and it turns over nicely. Flipped on the key and again jumpered start terminal, car starts right up. It has the solenoid mounted on the starter. The wire to the terminal is secure, no sign of corrosion. Did not have my voltmeter or even a test light with me to check for start signal voltage at terminal. Looking for possible causes of no signal or insufficient start signal voltage or current. Could it be the key switch/start switch? (If so, where is it located, at key switch, or in column)? Or possibly the supply to that switch? Thanks in advance for any advice/guidance, Iam really not familiar with the Bird.
-Jim.

Obtained a wiring diagram, tested for a start signal at the trans range sensor, nothing. Checked at the anti-theft output, nothing. Input, nothing. Guessing it is probably the ignition/starter switch. Possibly even adjustment of same. Do these use an actuator rod through the steering column, like a GM car?