The spark is started with the CKP(crank position) sensor detecting the crankshaft turning.
It is located behind the main pulley, behind the pulley is a wheel that looks like a gear with teeth but with one wider tooth, the CKP sensor reads the teeth passing by and that causes a pulse in the computer(PCM), wider pulse is #1 TDC.
This starts and times the spark.
CPS(cam position sensor) times the fuel injectors, just FYI.
Anyway the CKP sensor is the only way the PCM knows you want to start the engine, and it is the ONLY sensor that can cause a no start.
But...........the CKP sensors rarely fail, not never, but it certainly isn't common.
I would give it a look and make sure connector is clean and tight, no moisture inside.
PATS(passive anti-theft system) on an '03 Ranger would be Type E so starter motor wouldn't work if this was a PATS issue.
Next would be PCM, the ignition module is IN the PCM on yours so all you really have to get spark going is:
And wiring in between.
Does the CEL(check engine light) come on when you turn on the key?
That means PCM is getting power.
If not it may be a blown fuse.
It might be worth while to get/rent an OBD2 reader and connect it to the PCM, see if you can "talk" to the PCM, basically a sanity check to see if PCM responds normally.
If it does then you may get some trouble codes that are helpful.
I can't remember the exact years but I believe it was early-mid 2000's, Ford moved the PCM connector to the upper firewall, this turned out to be a bad idea because water could leak in from the rear hood gasket, and this caused odd shorts, very hard to track down.
They came out with a cover for this connection.
Might be worth a look.