New to Forum and need help with instrument cluster circuit board

Discussion in 'New Member Welcome Center' started by 74kingranch, Oct 29, 2015.

  1. 74kingranch

    74kingranch In First Gear

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    Hey everyone, joined today and looking for some advice, help, guidance. I have a 74 Ranchero 500. 460, c6 all factory with a/c. Owned it since around 1990 and was my daily driver. Finally got around to restoring it. Virtually every piece has been replaced, rebuilt, repainted, re chromed or reupholstered. It is beautiful. I'll attach pics of it as soon as I figure out how. The only thing that I have come up short on has been my dash lights. Ive replaced bulbs and suspect the circuit board on the back is bad. Who sells new circuit boards for these? Not having all the dash lights work is driving me crazy. I can't even find circuit boards for the Torinos. Less than perfect on this car is unacceptable to me. Any help is greatly appreciated, thanks in advance!
     
  2. 72GTVA

    72GTVA Administrator Staff Member

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    Instrument cluster or idiot lights?

    Often, if the circuit board is intact, a cleaning of the exposed contacts at the printed circuit connector and at the light sockets with an electrical board/component cleaner such as "Deoxit" (sold at Radio Shack) and cleaning the contacts with a typewriter eraser will restore the electrical connectivity. Be gentle as you are as thorough as you can be. Take plenty of time.

    No one (yet) reproduces the printed circuit.

    Source for the power to the dash lights is the headlight switch, and often the rheostat on the switch goes bad - the option there is to replace the headlight switch. From the headlight switch, the light blue/red stripe wire through the harness is the illumination wire. You can test that wire at the printed circuit connector for voltage and proper operation of the rheostat.
     
  3. 74kingranch

    74kingranch In First Gear

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    Thanks. Helpful start to know which wire is the power for those lights. I'll start at the switch and go from there. BTW talking about the gauge illumination.

    I actually saw a guy do a DIY circuit board on a Torino forum out of a plastic pallet sheet and copper foil tape! I guess it worked fine (he said) but I really don't wanna go that route. I think his issue was bigger than just gauge lights though. I'd rather just get 194 bulb sockets with the pigtail wires and hook all the lights up in series that way with power from the switch and a ground. I actually have alot of those sockets and may be what I end up doing if it is more involved than the headlight switch or rheostat.

    I appreciate the tips! Nice looking Ranchero by the way! Why are these things so cool? Do we just have superior class and taste?
     
    abrewsterarchitect likes this.
  4. 72GTVA

    72GTVA Administrator Staff Member

    Messages:
    9,754
    Location:
    Chesapeake, VA
    I neglected to mention the first simple check - the fuse in the fuseblock...

    In my experience repairing or just cleaning the printed circuit results in the best result. On occasion, the printed circuits show up on e-bay and another option is to purchase a good used cluster with a good printed circuit - just beware that there are 4 variants over the year groups from 1972 thru 1979 and there are substantial changes in the year groups. You are best served, if you go that route, the make certain you are getting a 1976 cluster.

    Thank you for the complement on Goldfish - it is a '72 429 4V car.
     
  5. Turtle

    Turtle In First Gear

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    I inherited a 78 Ranchero 500 last fall. Had the same problem, dash lights not working so I pulled the instrument panel out to take a look. The rear panel where everything was tied on fell apart into little pieces of white plastic. Be careful! I looked around the web and couldn't find a new one and looked in the wrecking yards to no avail. I finally settled down and built a rear panel out of 1/4 " plywood and rewired the whole thing because the plastic panel had a specific plug in that disintigrated too. It worked but I then realized that most of the gauges had quit working. I made a second panel out of sheet aluminum. The 80 mph speedo and the tach still worked along with the amp gauge, but I had to buy new gauges and install them. After about a month of off and on craziness I finally got it all together again and it still looks pretty much stock and I've got everything working now. Good luck with yours!
     
    Kane likes this.
  6. ribald1

    ribald1 Banned PLATINUM MEMBER

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    If you run across a GT gauge cover, the Autometer gauges work with the holes.
    You just have to work out a support arrangement.
     
  7. parts4me

    parts4me In Maximum Overdrive

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  8. Kane

    Kane In First Gear

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    Location:
    Sothern California
    I have a 1979 Ranchero 500 with the same crumbling instrument cluster issues. I was hoping to rebuild it as well. Do you have a diagram of your handy work?
     
  9. PonyExpressRider

    PonyExpressRider In Maximum Overdrive

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    If all else fails... check out Instrument Specialties... they provide rebuilt clusters and Dashboards... but not cheap!
     

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