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Jerry, Master Mechanic
Category: Dodge
Satisfied Customers: 1754
Experience:  ASE Master tech, 30 years exp. troubleshooter, driveability tech
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I have a dodge magnum 2005 rt. the tachometer doesn't work

Customer Question

I have a dodge magnum 2005 rt. the tachometer doesn't work all other instruments work. can you help?
Submitted: 1 year ago.
Category: Dodge
Expert:  vipertech763 replied 1 year ago.

Afternoon, there is a self test you can perform on the cluster assembly to see if all the lights and all the gauges will work. Here is what you need to do step by step. Try it and see if the tach moves during the self test. Let me know what happens


The instrument cluster actuator test will put the instrument cluster into its self-diagnostic mode. In this mode the instrument cluster can perform a self-diagnostic test that will confirm that the instrument cluster circuitry, the gauges, and the indicators are capable of operating as designed. During the actuator test the instrument cluster circuitry will position each of the gauge needles at various calibration points and illuminate all of the segments in the Vacuum Fluorescent Display (VFD) units.

Successful completion of the actuator test will confirm that the instrument cluster is operational. However, there may still be a problem with the CAN data bus, the Powertrain Control Module (PCM), the Front Control Module (FCM), the Transmission Control Module (TCM), the Occupant Restraint Controller (ORC), the Controller Anti-lock Brake (CAB), or the hard wired inputs to one of these electronic control modules. Use a diagnostic scan tool to diagnose these components. Refer to the appropriate diagnostic information.

    • Begin the test with the ignition switch in the Off position.
    • Depress the odometer/trip odometer switch button.
    • While still holding the odometer/trip odometer switch button depressed, turn the ignition switch to the On position, but do not start the engine.
    • Release the odometer/trip odometer switch button.
    • The instrument cluster will simultaneously begin to illuminate all of the operational segments in both VFD units, and perform a bulb check of each operational LED indicator. The VFD segments and LED indicators remain illuminated as each gauge needle is swept to several calibration points and back. If a VFD segment or an LED indicator fails to illuminate, or if a gauge needle fails to sweep through the calibration points and back during this test, the instrument cluster must be replaced.
    • The actuator test is now completed. The instrument cluster will automatically exit the self-diagnostic mode and return to normal operation at the completion of the test. The actuator test will be aborted if the ignition switch is turned to the Off position, or if a vehicle speed message indicating that the vehicle is moving is received from the PCM over the CAN data bus during the test.