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Help locating VSS source

Discussion in 'The Injection Section' started by Mastiff, Nov 25, 2006.

  1. Mastiff

    Mastiff 1/2 ton status Premium Member

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    I think my 83 K5 (with factory cruise) has a VSS signal coming out someplace, going to the cruise box. I removed all the cruise stuff under the hood. Can someone help me identify the VSS wire? I'm assuming it's what the 7747 ECM wants.
     
  2. b454rat

    b454rat 1/2 ton status Premium Member

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    Think it runs off vacuum, not a VSS. But that would be on the back of the speedo...
     
  3. Russell

    Russell LB7 Tahoe Status Premium Member GMOTM Winner

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    Yep, VSS is located on the back of the speedometer. You'll want to make use of the brown wire coming off of the connector for your ECM.

    And b454rat -- In 83 cruise control was switched from a vaccum servo style to an electronic style that uses a speed sensor just like modern vehicles :)
     
  4. Mastiff

    Mastiff 1/2 ton status Premium Member

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    You sure about the brown wire? I was digging through the diagrams in my shop manual, and it looks like there is supposed to be a little box attached to the back of the speedo, then ground, power and a yellow wire with the VSS signal. I haven't dug around in the truck yet to check this stuff out.
     
  5. Russell

    Russell LB7 Tahoe Status Premium Member GMOTM Winner

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    Might be yellow, mine was brown, but mine came from a car, not a truck. Either way, the color of the signal wire doesn't matter, just don't hook the pink / black (12V), or black / white (ground) to the ECM's VSS pin :)
     

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