Another NSS question...

Discussion in 'General IH Tech' started by Sozzy, Sep 1, 2020.


  1. Sozzy

    Sozzy Farmall Cub

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    I searched and couldn't find the answer to my specific question...
    I am almost done rewiring my Traveler with the Kwik Wire kit. There is one purple wire for the neutral safety switch. Seeing as how I am using an aftermarket harness, do I need to wire it through the relay? If I do, does anyone have a schematic of how to do the wiring? What wire gets run to where? Thanks.
     
  2. scoutboy74

    scoutboy74 Lives in an IH Dealership

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    This is the part of your rewire project where you will need to deviate from the kit instructions and refer to the schematic in your FSM. There are two components to the neutral start system. The under dash relay that is identical to your horn relay, and the switch housed in the transmission. The switch serves a dual purpose. The outer two terminals are energized when the key is ON and the gear selector is placed in 'R' to power your backup lights. The center terminal supplies the momentary path to ground for the under dash relay when the selector is placed in either 'P' or 'N', thus allowing the signal to pass from the IGN switch to the starter solenoid when turned to Start. So, you need a wire running from the trans switch center terminal to the appropriate relay terminal. Then your feed from the IGN switch Start terminal must terminate to the appropriate relay terminal. Then a wire must run from the remaining relay terminal to the solenoid 'S' terminal. Your kit instructions are geared to hot rod enthusiasts with the assumption of either Chevy or Ford power train. That's why this method tends to be omitted in their instructions.
     
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  3. stevewillis

    stevewillis Farmall Cub

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    I have that wiring kit. The setup for a Scout II is a little different than the Kwik Wire instructions show. The NSS in the Scout II is a single wire that is switched to ground when the transmission is in Park or Neutral, which triggers a relay connecting the ignition switch to the starter motor. That relay is the "switch" shown in the Kwik Wire instructions, and not the Scout NSS itself.

    I used a modern Bosch-style automotive relay with mine, which you can buy anywhere. The wiring is like the attached diagram here, which I stole from the Internet. Details:
    • Note that there are two pieces to the Kwik Wire #19 (purple) wire. One comes from the ignition switch, and one is in the harness for connection to the starter motor solenoid.
    • Connect Kwik Wire #19 (purple) from the ignition switch to relay pins 30 and 86. This is shown as a connection to a battery in the diagram below, rather than to an ignition switch. Your setup is actually the same, but with the ignition switch between the fuse and the relay pins in the diagram.
    • Connect a wire from the Scout II NSS to relay pin 85. This wire is not part of the Kwik Wire kit. It is shown as the "Ground Trigger Source" in the diagram below.
    • Connect Kwik Wire #19 (purple) from relay pin 87 to the starter motor solenoid "ST" terminal. This is shown as the "Device" in the diagram below.
    How it works:
    • The relay pins 30 and 87 are now the NSS shown in your Kwik Wire diagrams.
    • When you turn the key, power is applied to pin 86. If a ground connection is also present at pin 85 (because the transmission is in Park or Neutral), then the relay will internally connect pin 30 to pin 87, which sends the signal to the starter motor solenoid to engage.
    relay.jpg
     
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  4. Sozzy

    Sozzy Farmall Cub

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    Very well explained. Thank you. I pulled the relay from under the steering column but still have it. Think I'll mount it on the firewall, in the engine bay. Once I get this sucker hooked up, I can install the new dash and gauges and start her up for the first time since about Christmas last year...
     
  5. Sozzy

    Sozzy Farmall Cub

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    My relay only has 3 blades and they are labeled 1,2,and 3. Do I have to wrong relay? If not, which blade is which? Thanks.
     

    Attached Files:

  6. stevewillis

    stevewillis Farmall Cub

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    That is an original relay, not the modern Bosh-style that I used. Based on my read of the field service manual:
    • Terminal 1 of that relay connects to Kwik Wire #19 (purple) from the ignition switch.
    • Terminal 2 of that relay connects to the neutral safety switch (use your own wire...not part of the Kwik Wire kit).
    • Terminal 3 of that relay connects to the 'S' terminal of the starter solenoid motor with the other piece of Kwik Wire #19 (purple) in the harness.
    I can't tell from your photo whether all the relay terminal numbers are labeled on the relay itself. If not, Terminal 1 (power from ignition switch) is the one in a row by itself, farthest from your left thumb in your photo. Terminal 2 is in the lower left of your photo, and Terminal 3 is in the upper left (I think I see a "3" stamped beside that one in your photo).
     
  7. stevewillis

    stevewillis Farmall Cub

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    Whoops. You said they are labeled in your post, and I even quoted it in my reply. Ignore my last paragraph.
     
  8. Sozzy

    Sozzy Farmall Cub

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    Very helpful. Thanks. Now I have to wait for a new NSS pigtail to get here.... Can't find what I did with the old one.
     

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