Well after an all niter, I finally got my 400 in and ready, but I can't seem to get any juice to crank it. Everything else works, but the start circuit. I have a diagram, and it seems the neutral / safe / back up light circuit is dead.
Checked my harness and it seems everything is in place. Any ideas. Ignition switch, starter relay etc.
All of this worked before, too,
(86 truck used to be 318, now 400, 727 4wd )

the first check would be to determine if the starter relay is getting juice when the key is in START. If yes, is the starter/solenoid getting juice under the same condition (from the starter relay)?

Have you tried moving the shifter while holding the key in the start position?

nope nada on both

yes, I wiggled cussed talked sweet you know the whole routine

I'd jump 12V to the "ign" terminal on the starter relay & if it cranks I'd trace it back to the ignition switch & find the "open". if no crank I'd ground the neutral safety switch terminal on the starter relay & turn key to "start" & if it cranks I'd trace that wire back to the trans & see why it's not grounding or just permanently ground it there at the starter relay being aware that the eng will now start & the vehicle will move if you start it in gear.

not to sound dumb, but would you explain how to ground the neutral switch. thanks - mike

We are all at different levels & I am regularly awed by the skill level/knowledge of the guys here & I learn more every day. There will be one terminal on the nss with a wire that goes back to the side of the trans. You would jump from this male terminal on the nss itself several inches to the base mounting bolt on the nss effectively permanently grounding it. When it's functioning, putting the trans in N or P grounds this wire at the other end at the trans, you're just doing the same thing(& permanently)upstream at the nss which is why it would now start in any gear as the trans is no longer controlling the grounding. EDIT those later nss's have way more connections than the 70's basic 4 terminal ones so ID them carefully.

thanks - I hope this will fix it - Mike