Back up lamp and NSS pinout

Discussion in 'OEM and Custom Interiors' started by Usanumber1, Jan 10, 2021.

  1. Usanumber1

    Usanumber1 Newbie

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    Have a 1999 K1500 6.5TD Suburban. Swapped in a 12V, and just installed a Chevy NV4500. (Has dodge input and bellhousing.) Question: I have the 7 pin NSS harness connector C2 from the 4L80E in front of me, I’m looking to wire in the neutral signal and back-up lamps. The only pin-out I’ve been able to find doesn’t quite line up with mine, I’d presume the pins are the same but the wire colors are moved around. I will attach below. Looking for help in which two wires are to head back to the trans. Thank you.

    My connector wiring is as follows:
    A YEL
    B LTGRN
    C PNK
    D BLK
    E PPL
    F LTGRN
    G PPL/WHT

    DFF5F058-9BB2-4AFE-8123-2F0799E1130C.png
     
  2. AK49BWL

    AK49BWL GMT400 Forever!

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    The back up lamps will be wired up to a switch on the (left?) side of the NV4500. Light Green is the reverse signal out from the switch, pink is power to the switch.

    The neutral safety should be instead wired to your clutch switch, and should be in-line with the ignition "Start" switch - so the wires for that down there aren't of much use anymore. You might need to connect the yellow wire on G with the Purple wire on E, that bypasses that particular NSS. (the pins may be reversed color-wise but the pin-out is the same, pins G and E need to be together to bypass)
     
  3. Usanumber1

    Usanumber1 Newbie

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    Awesome. That’s what I was thinking, but my wiring diagrams aren’t good enough to be sure. Please correct me if I got this wrong:

    C PNK and F LTGRN on my 7pin should go down to the top of the trans and mate up to the existing pink and lt green 2 pin connector.

    Add in the NSS under the dash in-line with the brake safety switch, this part is clearly detailed in diagrams.

    The old trans NSS, just permanently splice those and abandon it and the rest off the harness.
     
  4. AK49BWL

    AK49BWL GMT400 Forever!

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    Correct, except for one thing... The clutch switch has two switches, one for clutch status which is a normally closed switch, used to kick off cruise and should be inline with the brake switch's normally closed output. The other switch is for the starter, and that one's normally open.

    upload_2021-1-10_21-40-4.png


    The following shows the other switches (status)

    upload_2021-1-10_21-42-30.png

    As you can see, the pin designations are different between the two clutch switches.
     
  5. Usanumber1

    Usanumber1 Newbie

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    Excellent. You’ve been a great help.

    Where do get those color coded diagrams? Alldatadiy is helpful, but leaves much to be desired.
     
  6. AK49BWL

    AK49BWL GMT400 Forever!

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    I use Mitchell OnDemand 5 for my diagrams.

    I've uploaded the diagrams for many different things, including 94, 97, and 99 GMT400 trucks, so you should be able to find just about anything wiring-related for a Vortec-based truck here lol.

    https://www.ak49bwl.com/other/wires/
     
  7. Usanumber1

    Usanumber1 Newbie

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    The truck starts, sort of. So I have pins/wires connected as we discussed. It cranks/turns over/runs after a few mins/tries. However every attempt I make, I can hear the starter solenoid make the pronounced CLICK, but there's no turning of the motor on the flywheel. This leads me to believe there's another switch that is either not getting the proper signal.

    The other 3 pins on the NSS, A, B, and D. Park/Neutral Signal, Park Neutral Position Switch Park Signal, and Ground, respectively. Do those need to be addressed as well?
     
  8. AK49BWL

    AK49BWL GMT400 Forever!

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    If the starter solenoid is engaging, the problem is no longer the switches... Your starter could have quit on you, or maybe check the starter relay contacts for corrosion - also what is the battery voltage when cranking?

    The wires you're referring to only go to the gear shift indicator in the cluster, and have no effect on the starting system at all.
     
  9. Usanumber1

    Usanumber1 Newbie

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    That’s what I was thinking as well. It’s a brand new Remy starter, but it’s also chinese so that’s probably the problem.
     

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