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1990 Ford Escort Question: Tach does not work 1987 GL



, Ritzville, WA, October 22, 2010, 13:58

Tach does not work 1987 GL
is the intrument panel voltage regulator at issue or a bad tach unit? how to tell which?

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  • Answer #1

    October 22, 2010, 15:22

    The instrument voltage regulator is for the temp and fuel gauges, the tachometer works off a different circuit. If your temp and gas gauge work then the voltage regulator must be OK. The tach works on a different principle than the temp and gas gauges. The tach unit could be faulty or ther could be a problem with the tach signal from the engine. The DrkGrn/Yel wire at the ignition coil is where the tach sigmal originates.

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    , October 22, 2010, 19:16

    Temp & gas work fine; will try to check the DrkGrn/Yel wire. is there a way to use, say a 9V battery and tap the DrkGrn/Yel wire to see if the tach needle bounces? or to wire a circuit to simulate a 500 to-some few thousand rpm 'fake?' signal to test the tach?
    [back when I used to make one of those...

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