Opened up the distributor, removed the rotor, removed the two screws holding down the rotary vane cup, and surprise, no wires visible.
I do note that Section 03-07A, Distributor Ignition, 3.0L of the 93 Ford Range shop manual is not what is installed in my Ranger and the distibutor has never been changed since I bought the vehicle new in 1993.
The illustration on page 03-07A-3 is not the right one for my truck, I can only guess that it is for the California emissions or something. Also, on page 03-07A-7, the exploded diagram for the 3.0L distributor shows a pigtail of wires extending out of the side of the distributor with a round plug and this is not the distributor that was factory installed on my truck.
This is probably why this is so difficult, Ford doesn't seem to have any recognition of this particular 3.0L as nobody can seem to find any drawings that are correct for this combination. Very frustating.

 

From what I have been able to figure, which isn't very much, The distributor uses a hall effect unit to signal the module. One of the 4 wires supplies the source voltage, another of the 4 supplies a ground and the remaining two supply the signal to the module. I'm going to have to really dig into this in order to be able to explain which wires go where.
Also from what I have been able to uncover a 4 wire hall effect switch uses what is referred to an a shared ground with the other wires. I don't know about you , but I' m getting an education from this one. When I can explain the proper function , I hope I will be able to tell which wires go where so , back to the books for me! Thanks for the pix , it did help to make a lot of things more clear for me.

 

If you remove the plug from the piece in the distributor, can you with a mirror and flashlight see any markings on the sensor plastic. What I'm looking for is possibly a + sign, or a - sign or maybe a "0" that might make it easier to determine which of the wires could go where? We could use a voltmeter to maybe do some checking , but at no time can we use an ohmmeter because it could damage the sensor.
We could always ask a Ford dealer if he has one in stock and just maybe it would have the wiring instructions with it. I'll keep looking for addl info that might help.
When you do check the hall effect switch, do they have 4 pins at that point where the plug goes or do they show less pins?

 

There are four pins on the inside of the distributor plastic casing. there are no letters, numbers or other markings that I can see.