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Discussion Starter · #1 · (Edited)
Hello,

I have OEM dash wiring, but I have a non-stock shifter with a different neutral safety switch. The dash wiring has 4 wires that go to the switch on the shifter. Mine has only 3 as you can see below, and I have no idea which leads are for which wires. An OEM shifter harness won't fit, so I will have to do the wiring myself once I figure this out - any help appreciated.

Thanks.

 

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What you want to do is run the wire from the key switch that goes to the starter solenoid to the neutral start switch before it goes to the solenoid.

Easy way is just extend it from where ever to the switch on the shifter. It basicly is just a switch in series with the start wire. No power to the starter unless its closed.
 

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You should be able to use an ohmmeter to determine which terminals have continuity with which when the shifter is in reverse, neutral or park.
Since there is only three, one must be common, one for back up lights and one for starter solenoid.

{edi} No that ^ won't work, the key would have to be in the starter cranking position for the back up lights to work. :clonk:
 

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Discussion Starter · #4 ·
What you want to do is run the wire from the key switch that goes to the starter solenoid to the neutral start switch before it goes to the solenoid.

Easy way is just extend it from where ever to the switch on the shifter. It basicly is just a switch in series with the start wire. No power to the starter unless its closed.
do I have to do that if I have the OEM dash harness though? There is a plug with green two green wires and two purple wires and go to the shifter I believe
 

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I'm assuming what you have is an original column shift automatic car that you are converting to either a floor shift or new column shift that has a plug with three terminals on it.

If this is the case then here is probably what is going on. The existing under dash plug that has the two green and two purple wires connects to the back-up light switch and the neutral start switch. On the last car I looked at his is the same switch with terminals for the green plug and differential terminals for the purple plug. You will have to sort out which wires do which function but let's assume the green wires are for the back-up lights and the purple wires are for the start system. With the plug disconnected from the existing switch jumper the two green wires together and see if the back-up light work. Do the same for the purple wires and see if you can start the engine. Lets assume these wire do these functions.

You will then need to determine what the new switch three terminal switch does and if you can have both the back-up and neutral start system work from the same switch. I would, with an ohmmeter, measure the continuity of the terminals on this switch as I moved the shift lever. The obvious thing you are looking for is which terminals are closed or making contact when the shift lever is only in reverse. If the only time there is continuity on these two terminals is when the shift lever is in reverse then the green wires need to connect to these terminals to run the back-up lights.

Similarly measure the continuity of this switch while the shift lever is in park and neutral. If the manufacture of the shift system did it right there will be a condition where there is continuity (closed contacts) when only in park and neutral. The purple wires go to these terminals.

With only three terminals on the new switch one of the terminals will be used twice - meaning both a green and purple wire will be connected to it. You will need to experiment to get the switching and wires correct but it should work for you.
Al
 

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You can't combine two circuits that are meant to be separate.

Unless you get another switch, you won't have working back-up lamps.

The starter solenoid and switched ignition power must remain isolated.

Your purple starter wires would go to the two switch contacts that are "shorted" together only when the shift lever is in park/neutral.

I've haven't heard of a single switch transmission set-up that gets activated by park, neutral and reverse anyhow.
 

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Dean,

In '64, the ignition switch is non mutually bussed. Power will be lost during cranking. Even if power isn't lost, the "pink circuit" isn't designed to handle starter solenoid current. On and start are meant to be two different circuits.

Besides, how would one switch "decode" park vs neutral vs reverse vs drive etc? "C" "NC" and "NO" is slave to the mechanical linkage ;)
 

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Dean,

In '64, the ignition switch is non mutually bussed. Power will be lost during cranking. Even if power isn't lost, the "pink circuit" isn't designed to handle starter solenoid current. On and start are meant to be two different circuits.

Besides, how would one switch "decode" park vs neutral vs reverse vs drive etc? "C" "NC" and "NO" is slave to the mechanical linkage ;)
Gotcha :yes:


Was just curious if the 64 NSS wire colors were the same as later years.
 

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Discussion Starter · #10 ·
Okay sounds good, thanks for the replies. I will have to cut some wire since the OEM shifter harness has those plugs that don't fit. Either that or just get an OEM shifter so I have back-up lights.
 

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Discussion Starter · #11 ·
Well I found something interesting. It looks like the original Hurst neutral safety switch is supposed to have 4 terminals. One of mine looks broken off - very cleanly - which is why I believed it was only 3. Looks obvious now if you look at the pic in my original post.
 
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