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wiring a factory Repo(LMC) tach

Discussion in 'The Garage' started by suspectdon, Sep 7, 2006.

  1. suspectdon

    suspectdon 1/2 ton status

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    my 71 blazer has a the factory tach option but when i bought it the tach had been removed and sold....well i got one and i can't find any info on how to wire it, it has two blade conectors on the back and one screw in the middle....i bought the tach from LMC it came with no instructions. some help would be great.

    Richard
     
  2. dremu

    dremu Officious Thread Derailer Premium Member

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    Eh? If your truck had the factory tach, it should have the wiring harness.

    Donno 'bout the first-gens, but the later ones are marked for ground, +12V hot and the dizzy... IIRC, BAT and TACH for power and the dizzy, and I s'pose the screw would be the ground. Maybe some first-gen people would know for sure?

    -- A
     
  3. suspectdon

    suspectdon 1/2 ton status

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    anyone know anything more about hooking up a LMC tach? a picture of what wires hook to it woult be great!!

    Richard
     
  4. 68MUDSTUD

    68MUDSTUD OCD with shiny things

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    hey man, i just got one for my 71 k5... all there is, is a hot lead going from one side to the fuse box, put in the "unused" terminal i think? and 1 wire that goes through the firewall that plugs into my HEI, or negative side of your coil. :D
     
  5. 1985_K5_Silverado

    1985_K5_Silverado 1/2 ton status

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    I just looked on ebay and they have several 71 GM light truck factory shop manuals there. Would one of those have a wiring diagram that might help? I know 25 bucks isn't free, but it might be an option.
     
  6. 68MUDSTUD

    68MUDSTUD OCD with shiny things

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    dont get it man, ill give you a picture of mine if you want it. tomorrow ill go take some pics and get you more info.
     
  7. suspectdon

    suspectdon 1/2 ton status

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    thanks,

    do you know which is which? will i burn it out if i hook it backwards?
    thanks for the help !! i'll be working on it this weekend.
    if its not to much trouble a pic might help.

    Richard
     
  8. suspectdon

    suspectdon 1/2 ton status

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    thanks for the help i worked on the truck this last weekend and got it put back together and running around...rusy / headers are fun with the 4 speed having a tach is great ! i never knew what rpms i was at and with the rust headers i sounded like i was killing hte thing!!! but with the way the sound is i was only taking it up to 2200, 2500 some times!!...full exhaust and 32x11.5 coming in the winter/fall.

    thanks,
    richard
     

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