Instrument Cluster Rewire '79

Discussion in 'Electrical Systems' started by br0nxb0mb, May 30, 2017.

  1. br0nxb0mb

    br0nxb0mb New Member

    May 5, 2017

    Have tried searching for an answer to my question to no avail. I have a '79 Berlinetta with the stock "idiot light" cluster. My pcb is in bad shape and I'd like to do away with it all together. I already have aftermarket temp and oil pressure gauges fitted into the stock cluster. I plan to wire some 194 twist in pigtails for lighting. I understand I will lose some of the cluster functions like idiot lights, high beam and turn indicators, not really worried about that so much.

    My question is in regards to the stock tach. The brown wire in the harness is supposedly the tach signal from what I read. There are 2 studs on the back of the cluster in the tach area that are marked "coil" and "12v" under the pcb. Can I wire the brown wire to the coil stud, and give 12v to the other and have the tach work without having to use the pcb (printed circuit board). Would I need to supply any type of ground to the cluster for the tach to work?

    I plan to do something similar with the stock fuel gauge and battery gauge, hardwiring them in.

    Any help or additional info would be appreciated.
  2. rchydzik

    rchydzik Veteran Member Lifetime Gold Member

    Nov 13, 1999
    Colbert, WA USA
  3. Rayden2009

    Rayden2009 Member Gold Member

    May 12, 2016
    Calgary AB
    I am beginning the process of wiring in some new Speedhut gauges. All gauges need to be wired to 12V ignition source. From my research, it looks like the pink wire on terminals 3 and 8. Why are there 2 power terminals? I plan to just steel power from terminal 3, but I am wondering what the 8 terminal power is for. Will I be ok if I ignore terminal 8 and just splice the gauges to the pink wire on terminal 3?

  4. Jim Streib

    Jim Streib

    Apr 6, 2004
    Saint Louis, MO USA
    I wonder if it has to do with how the circuit board is configured after the plug to different things ?. Maybe the design or layout required two different locations.

    You should be able to take the fuse out of the fuse block for that circuit and then see if both pink wires go dead and then if they do, then you can use one and cap the other off.

  5. Rayden2009

    Rayden2009 Member Gold Member

    May 12, 2016
    Calgary AB
    Great advice. I will do that. Thanks

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