I have a 1975 F250 with 390 auto, it's the supercab camper special, also has points ignition if that matters. It started fine yesterday but today after I replaced the turn signal switch it won't start. The switch was just worn out so you had to wiggle it to get everything to work. After I replaced it everything checked out and I went to start it back up but it wouldn't start (no cranking). Here is what I know:

-Power from ignition switch when in start mode
-No power to starter (used remote starter and it cranked over)
-No power to starter solenoid switched power wire so somewhere between the switch and that wire there is a problem.
-Neutral safety switch is on lower steering column and I didn't touch it, connects all look fine.
-Tried wiggling the shift handle while trying to start in park and other gears but didn't make a difference.
-Underdash fuses are fine.
-When replacing the turn signal/Hazard switch none of the wiring seemed related to the starting system so I don't think it's anything from that.

Basically what is need is a simple wiring diagram from the ignition switch to the starter solenoid, as my problem is somewhere in between. The manual I have has terrible wire diagrams that doesn't help at all. Any help is appreciated, the turn signal was the last thing I needed to get it back on the road.

 

I figured it out, the neutral safety switch was very dirty. The steering column shaking must of been the last straw for it. I cleaned it, but it might be time for a new one since I still can't get the reverse light part of it to work.

 

Glad to hear you got it worked out. You can troubleshoot the reverse light portion of the switch by ohming it out, or making sure power is coming into the connector.

 

I did the continuity test for the neutral switch and also the reverse. The reverse light portion had no continuity until you hold it just in the right place in reverse. Even after I cleaned it it did that, so I might try disassembling it sometime and making sure everything is tight.

 

I have the same truck with a similar issue. Batt good power to one side of the solenoid but I have no power anywhere nothing works. If I have the key on and cross the terminals I can crank the engine but nothing from the cab at all. I checked the fuses all good in the cab. Ideas please.

 

Is it an automatic trans? If so check the neutral safety switch .

 

Neutral safety switch won't cause loss of power to the entire cab...you need to check your fusible links coming off the main post of the solenoid...