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Tach hookup

Discussion in 'The Garage' started by epurdy2005, Aug 31, 2006.

  1. epurdy2005

    epurdy2005 Registered Member

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    I have a tach mounted on my dash and it had to be hooked up at one time. Its got a red black and green wire.....If I put the red and black on the battery I get the backlight to come on. But where do I put that green wire? I guess I've never hooked one up before.

    Thanks
    1982 K5 Blazer
     
  2. NEK5

    NEK5 3/4 ton status Premium Member

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    if its an 82 i`m not sure where it goes, but on my 90 the green wire went to the positive side for the injectors, i think yours would tie into the pos. side of the coil....may be and most likely wrong, someone else should chime in
     
  3. Hermy13

    Hermy13 Registered Member

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    If you are running hei there should be a spot on your cap that says tach hook it there
     
  4. dontoe

    dontoe 3/4 ton status GMOTM Winner

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  5. epurdy2005

    epurdy2005 Registered Member

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    wow thanks for the diagram!...So will I need to splice into a wire or is there a metal leed there to attach the wire. Thanks...Might be a dumb question but i'm at work and don't have a dist. to look at.
     
  6. dontoe

    dontoe 3/4 ton status GMOTM Winner

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    It's a male tab at the cap..............just get some female "blade" connectors at the Auto parts. Blue plastic insulator is the correct size.
     
  7. vortec

    vortec 1/2 ton status

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    nice diagram, there. since the tab points straight down, it can be a little tricky to make sure the female connector is actually seated properly on there, and not just wedged in next to the tab. i used an inspection mirror to be sure.

    and, if at all possible, ground to the engine block or frame. grounding to the dash or sheetmetal can lead to undesirable results, like irratic operation.
     
  8. NEK5

    NEK5 3/4 ton status Premium Member

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    x2! my ground will be going down to the frame soon enough
     
  9. epurdy2005

    epurdy2005 Registered Member

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    Sounds pretty simple......Thanks for all the help.
     
  10. KevinsK5

    KevinsK5 1/2 ton status Premium Member

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    All my leads save for green are under the dash. Light and power go to the fuse block, I have mine grounded to the dash and it works fine. It would be a PITA to run a tach wire down to the frame.
     
  11. NEK5

    NEK5 3/4 ton status Premium Member

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    how so? just run it down to the floor, drill a little whole then screw to frame, not that hard, or maybe its just that i only have half a carpet?:D
     
  12. vortec

    vortec 1/2 ton status

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    honestly, for testing, i had it alligator clipped to the dash, and it worked fine. but when i actually installed it, i drilled a tiny hole in the firewall, popped a grommet in, and bolted the wire to the cylinder head. a little more effort, but it's the right way.

    just don't go digging through my k5 taking note of everything that isn't done "right". between the po's inneptitude and a few of my improvised quick fixes, i certainly can't claim that everything is by the book. :o
     
  13. KevinsK5

    KevinsK5 1/2 ton status Premium Member

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    Agreed. If my tach ever quits, I'll try a different ground. Every gearhead has his own way of doin it and if it works what the hell? Kevin
     
  14. Chevy305

    Chevy305 6 Lug 14bsf Status Premium Member GMOTM Winner

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    My Sunpro tach has 4 wires. Red Green Black White. The red goes to ignition hot, green goes to the dissy, black goes to ground, and white goes to light switch for the backlight.

    I have my tach grounded to a bolt on the e-brake bracket. Well that goes through the frame so close enough. :rolleyes: Whatever, ground has never been a problem for me. But what I do recomend is to run an in-line fuse because I have burnt 2 tachs before and they aren't real cheap either.
     
  15. epurdy2005

    epurdy2005 Registered Member

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    tach worked great.........I did find the white wire inside pluged into the fuse panel......The wiring on this truck is a nightmare.....Somebody took all the bulbs out of the dash to power stupid stuff.......One step at a time..Got the tach workin so we are getting there.
     

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