Maybe I missed it....

How did you determine you are getting low voltage on that wire? What is the voltage?

Did you test it with the wire connected to the solenoid or disconnected?

I don't know much about that transmission position switch on the transmission, except that it is there. I wonder where it gets power? Is it from the ignition switch or somewhere else?

 

I was setting up my test light so my assistant could see if it lit when I turned the key on and it glowed faintly, I compared it with the glow when hooked to the battery, did not try a meter on it but the light was really dim. That was with the wire off. I can't quite figure out the diagram but...I suspect that the route for electricity is fuse box to ignition switch, ignition switch to trans position detector and trans position detector to solenoid. Oddly enough the schematic for it shows switch to fuse then to solenoid but the fuse depicted in the diagram has power all the time, not only when switched and it doesn't make sense to go that way anyway.

 

Been through the ignition switch and it checks out OK. The line out of that switch is Red/Lt Blue and is fairly large. It does not go to the junction box. I got the bottom off of the junction box and the wires that feed the switch come out of there at the spaces indicated for it. Could the location detector switch on the trans be the problem? (I guess anything can go south). How would I test it? How does it come off? I can't see any bolts on the one in the garage, does it unbolt from inside the pan?

 

Sorry, I don't know I've not worked with that piece before

 

Next step will be to get under there and disconnect that position sensor and see what I can find. First I'll have to button the rest of the stuff back up and get it over onto the concrete, I'm going to need my creeper. At this point I could just splice right in at the column and bypass that selector and keep my ignition switch (avoid another button on the dash) and I am approaching that point. I do prefer to keep things original though, if I can.

 

Did you make any progress on this today?

 

Very little, check here. I started another thread including 'transmission' to get Mark Kovalsky's attention on it.
https://www.ford-trucks.com/forums/1...on-sensor.html