If you either get no rpm or its erratic, then change the Instrument cluster as one unit. RPM cannot be fixed or changed. You either have to buy a used unit from a junk yard or buy the cluster new at the dealer. Its expansive, I would buy a used one from a salvage yard for around $75-150. Good luck. I have 15+ years as an automotive technican. Trust me.
The RPM gauge is connected to the same wiring on as all the lights on the dashboard. A faulty RPM gauge can be replaced but requires removing the whole dash from the vehicle.
your rpm gauge works off your engin your speed gauge works off the transmission where the cable slides into the transmission tha plastic geer is probably stripped
Chack the fuse. If it's not the fuse, it's a sensor.
replace the printed circuit board behind the tach gauge. $15.00
why doesn't my rpm gauge and temp gauge, fuel gauge not work
First off, the correct terminology is tachometer, not RPM gage. And second, we do not have enough information on your problem to give you a proper diagnosis, thus we can not tell you how to fix it. My suggestion would be to see a mechanic.
To fix the RPM gauge on a 2004 Kia Optima, first check the vehicle's fuse for the instrument cluster, as a blown fuse can cause the gauge to malfunction. If the fuse is intact, inspect the wiring and connections to the gauge for any damage or corrosion. If these steps don't resolve the issue, the problem may lie with the gauge itself or the vehicle's Engine Control Unit (ECU), requiring replacement of the gauge or professional diagnosis. Always consult the vehicle's service manual for specific troubleshooting steps.
while driving the rpm gauge work perfect, when start accelerating the rpm can not exceed 3 with interruption in the engine
Your engine is not running or your "RPM gauge" is broken.
rpm
Get to a shop quick.
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