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#1 |
Registered User
![]() Join Date: Dec 2012
Location: Vancouver, Washington
Posts: 1,644
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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?
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1968 Chevrolet C/10 LWB - 327, TH350 - 4/5 Drop |
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#2 |
Registered User
Join Date: Aug 2006
Location: Redmond, WA
Posts: 6,332
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Re: Neutral Safety Switch wiring
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.
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1970 GMC Sierra Grande Custom Camper - Built, not Bought 1969 Pontiac 2+2 427/390 4-speed Coupe 1969 Pontiac 2+2 427/390 4-speed Convertible Last edited by davepl; 05-24-2018 at 12:14 PM. |
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#3 |
Msgt USAF Ret
![]() ![]() Join Date: Jan 2005
Location: Kalamazoo, Michigan
Posts: 8,714
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Re: Neutral Safety Switch wiring
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.
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VetteVet metallic green 67 stepside 74 corvette convertible 1965 Harley sportster 1995 Harley wide glide Growing old is hell, but it beats the alternative. |
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#4 |
Registered User
![]() Join Date: Dec 2012
Location: Vancouver, Washington
Posts: 1,644
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Re: Neutral Safety Switch wiring
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?
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1968 Chevrolet C/10 LWB - 327, TH350 - 4/5 Drop |
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#5 |
Registered User
![]() Join Date: Jan 2018
Location: america
Posts: 99
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Re: Neutral Safety Switch wiring
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 |
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#6 |
Registered User
![]() Join Date: Dec 2012
Location: Vancouver, Washington
Posts: 1,644
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Re: Neutral Safety Switch wiring
Thank you, that helps too. Slowly but surely getting all the wiring in this thing back to specs! Ned
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1968 Chevrolet C/10 LWB - 327, TH350 - 4/5 Drop |
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#7 |
Account Suspended
![]() Join Date: Jul 2016
Location: Tacoma, WA
Posts: 6,873
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Re: Neutral Safety Switch wiring
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. |
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