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77 Corvette Speedo, Odometer, Tach Problems

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Old Jan 13, 2010 | 08:39 PM
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Default 77 Corvette Speedo, Odometer, Tach Problems

Hi Guys,

The speedometer and odometer on a 77 Corvette that I've working on do not work. The tach works on and off. Starting with the basics of where the cables or connections go, can someone walk me through how to trouble shoot and fix this issue.

Thanks,
Dave
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Old Jan 13, 2010 | 09:01 PM
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Speedo should be straight forward. It runs from the gauge to the rear drivers side of the transmission. Most times problem is a broke line but you can pull it from the transmission and check the cable and or gear.

Tach is straight forward as well. it connects to the positive / negative side of your coil. It does have a capacitor connected in line to help keep the needle from jumping.
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Old Jan 13, 2010 | 10:17 PM
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Also search Willcox's site for tech. help. Lots of good stuff there. There are several past threads on Forum search that can help also. mds...
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Old Jan 14, 2010 | 11:00 AM
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Thanks!
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Old Jan 14, 2010 | 12:44 PM
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On the 77 you have, exactly what are the gauges doing?

Is the speedo working and the odometer is not? If so, the first worm and magnet are out on the head and it will need to be repaired.

On the tach.. is there any function at all? When you turn the key on, (not run) does the tach needle go to zero?

Answer these, I'll check back later to see if we can help you.

Willcox Inc.
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