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Another Tach Question

Discussion in '1965-1970 Shelby Mustang GT350 & GT500' started by streetsnake, Sep 1, 2010.

  1. streetsnake

    streetsnake Member

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    I have an original shelby tach (3 wire). Where do I get a resistor to make it work? The gentleman who is working on it said he was going to build one for him but progress is very slow. He said that once he ran it through a certain size filament it work fine but just needs that resistor. Any help would be great. Thanks
     
  2. streetsnake

    streetsnake Member

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    I looked on cobranda's site and found what was supposed to be instructions for an orginal but it shows four wires vs. three????
     
  3. zrayr

    zrayr Well-Known Member

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    what year are we talking about?

    original tach for a '66 has only 3 wires. And no resistor needed.

    Z.
     
  4. streetsnake

    streetsnake Member

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    I believe it is a 66. But he said that the only way to get it to work was using a resistor. Maybe he is trying to hook it up wrong. He's a professional engine builder and old/current drag racer but you never know. What is the correct way? Is there a good diagram to refer to. Thanks for you help.
     
  5. zrayr

    zrayr Well-Known Member

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    the resistor is a resistor wire that is between the tach and the coil.

    here is the wiring breakdown:

    the 3 tach wires are red, black, & blue/red

    the blue/red wire is power for the tach bulb.

    the red/green wire coming off the ignition switch plugs into the red tach wire (going into the tach)

    the black wire (coming out of the tach) plugs into the pink wire which is a resistor wire. The pink resistor wire goes to a multi-wire plug under the dash on the firewall. On the underhood side it continues as a red/green wire and goes to the ignition coil

    You do NOT want someone to fabricate this resistor wire. You can buy it from most Mustang vendors. NPD has it, page 160 on their catalog for $19.95. NPD Part number 12250-1

    http://npd.dirxion.com/

    hope I didn't make an easy answer too confusing.

    if your tach wires are different colors than what I have listed, then you do not have an original tach, or someone has hacked up the wiring.

    Z.
     
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  6. streetsnake

    streetsnake Member

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    Great. I'll call npd tomorrow. Thanks again
     
  7. streetsnake

    streetsnake Member

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    If I remember the wiring colors. They were black, red and green.
     
  8. zrayr

    zrayr Well-Known Member

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    you might check to see if you already have the thick pink (resistor) wire in place before ordering one. Are you adding a Shelby tach to a regular Mustang?, if so the pink resistor wire will be going right up to the red/green wire coming off the ignition switch, you just unplug it from the ignition switch and plug in the tach wiring as outlined above.

    Z.
     
  9. streetsnake

    streetsnake Member

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    Z,

    Sorry for the long delay. I finally got the time to mess with it. Installed the resistor wire and it works great. Thanks a million for the help.
     

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