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Tachometer not working after instrument panel overhaul

1491 Views 5 Replies 2 Participants Last post by  Louey
I just re-did my instrument panel, because the clock wasn't working. Now that I have everything back together, the tachometer no longer works.

I replaced the ribbon circuit board as a part of the overhaul.

It looks to me like the tach just feeds off the ribbon. I don't see how I could have done anything wrong. I don't see any other connections for the tach. What am I missing?

Where would be the best place to start looking for the problem?

I really don't want to pull the cluster again. That was a bear.
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You probably need to tighten the nuts a little tighter on the Printed Curcuit Board that are for the tach. Two small nuts that are right next to each other on the back side of the tach. You do have the brown wire connected to the - coil terninal? To make the tach work you need these connections 12 volts + which is pin # 7 in gauge harness plug , brown wire to - coil terminal, which is pin # 9 and a grounded tach.
This is how I test tachs. With the tach removed from the gauge cluster I would connect it to the car with loose wires with alligator clips on the ends. Connect to the battery positive and the other end to the 12 volt + post on the back of the tach. Then connect the -coil post on the back of tach to the - coil terminal. Then run a wire from the negative battery terminal to the metal housung of the tach for a ground. Start the car and the tach will work if it is in working condition. If it works then you have a problem with your PCB or wire harness or you do not have a ground. Or you are not making good contact where the harness plug goes into the PCB. Let us know what you find out.
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