1994 should have the starter relay built into the starter solenoid located on the starter motor, at least my '94 4.0l does.
So on the starter motor you should have 2 wires hooked up, the large battery positive cable.
And then the smaller "S" wire attached as well, Red/light blue stripe wire, this wire comes from Clutch switch on manual models and NSS switch on automatics.
Older Fords had the Starter Relay on the inner fender, not on the starter motor/solenoid, battery positive and starter motors large cable hooked up to the two larger posts on this Relay.
And the "S" wire, red/blue stripe also hooked up here to the smaller "S" terminal.
These two different systems don't have interchangeable parts.
There can only be 1 starter relay, it is either built into the starter motor or on the inner fender.
During the transition years Ford had what "looks like" a starter relay on the inner fender, it was just a power distribution point for the older setup until main harnesses could be changed.
If you got a starter motor with relay built in and then tried to use it with inner fender relay setup it wouldn't work, and visa versa.
Simply test would be to find the "S" wire, red/blue stripe, then hook up volt meter to it.
When key is turned all the way to START you should see 12volts on that wire, 0volts with key in any other position.
If not then go to Clutch Switch, you will see a Red/Blue stripe wire there, but it comes from ignition switch, it should have 12volts when key is turned to START.
If it does then clutch switch is probably bad, there is a PINK wire coming out of clutch switch that splices into the Red/blue stripe "S" wire that goes to starter relay, you can test this pink wire also, it is possible that the splice is bad.
If so then you can either track splice down or run a new "S" wire from the Pink wire to starter relay
Confusion on some terms:
Starter Solenoid is the tube on top of the starter motor, when powered it pushes starter gear into ring gear(flywheel), and when unpowered it pulls gear back away from ring gear.
Starter Relay passes power to starter motor/solenoid.
The fender mounted relay Ford used for many years was just that, a relay, but often called a solenoid, which is fine as long as everybody knows what part is being talked about.
A Solenoid causes movement when activated or deactivated
A Relay passes power or cuts power when activated and deactivated