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Q: Tachometer only goes up.

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The tachometer on my car only goes up very very slowly. It never goes down at all while driving even aat a full stop. It Takes about 25 minutes to reach the red. Once the car is turned off it automatically resets to 0. Even at red the car drives perfectly fine with no struggling, shaking or overheating what so ever. What is the cause and how can it be fixed?

My car has 179000 miles.
My car has an automatic transmission.

A: Hello and thanks for contacting YourMechani...

Hello and thanks for contacting YourMechanic. It seems that your tachometer is loosing voltage in the rheostat (the part that makes the meter work). The tachometer gets its signal from the computer or the ignition coil pack ground circuit. If the tachometer is moving up, but does not go down at all, then you would need to replace the instrument panel cluster (the part that has all of the gauges together). This will fix the tachometer situation. To verify this problem, you could have a certified technician from YourMechanic diagnose the tachometer and help you proceed with repairs.

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