Neutral Safety Switch wiring

[OregonNed]

My truck started life with a manual transmission, which was replaced with a TH-350 by a previous owner. I've seen what I believe is the wire that used to go to the transmission - hanging disconnected and taped down near the bundle that goes from the firewall to the starter. It is a purple wire. Now I am getting ready to install a floor shifter (new) with a neutral safety switch - (the old shifter did not have that option). What is the best way to newly wire the new switch?

[davepl]

The purple wire is the wire that carries current from the ignition switch to the starter solenoid. So any interruption of that circuit will act as a neutral safety.

Wire it to the provided neutral safety in the new shifter and you should be set!

I strongly encourage you to solder and make any connections in this wire PEFFECT, including any old cuts or splices from previous owners. If the purple wire is anything but perfect, you'll find that NOTHING happens when you go to crank it on a hot day.

That's the famous "Chevy Starter Heat Soak" problem and people throw starters and heat shields and all kinds of parts at it, but it's usually just a bad connection in the purple wire.

[VetteVet]

Here's a diagram showing the wiring of the start circuit.




Just follow Dave's advice and add the purple wire from the NSS to the S terminal on the starter. If you have the HEi distributor you won't have the coil wiring from the R terminal.

[OregonNed]

Thank you. So since the wire (purple) is not connected to anything now, there must be another wire supplying voltage to the solenoid. I am guessing I would trace out the wires, make sure purple is good from its source, connect it to the switch and then from there out to the solenoid?

[vinro]

The purple wire would need to be cut and connected to the NSS.
Check this thread...
http://67-72chevytrucks.com/vboard/s...d.php?t=755946

[OregonNed]

Thank you, that helps too. Slowly but surely getting all the wiring in this thing back to specs! Ned

[randy500]

If the truck is starting then some wire is connected to the solenoid (originally it was purple) but it doesn't matter.
What matters is that the key switch has a purple wire that engages the starter.
The purple wire from the key switch is the wire to interrupt for your neutral safety switch on your floor shifter.
Cut and extend that wire to your switch on the shifter.