The electronic sophistication of modern cars extends to the dashboard. Electronic instrument clusters display such critical data as speed, mileage, fuel level and malfunction warnings. A faulty instrument cluster may display inaccurate or nonsensical readings, or it may not operate at all. The error may stem from a voltage problem, or from incorrect grounding or a bad sensor. These complex panels usually require total replacement instead of simple repairs.
A faulty instrument cluster or wiring harness can blow a fuse, causing the instruments to go dead. If the replaced fuse blows immediately, then one of these two components probably has a short in it. Tracing the wiring circuit with a voltmeter can reveal the failure point in the electrical system, while checking the wiring harness with an ohmmeter can determine whether the power circuit has a good ground connection.
Electronic gauges depend on the accuracy of computerized sensors to feed them accurate data. AA1Car.com notes that if an isolated indicator misbehaves, the problem may lie with the individual sensor for that indicator. If indicators fail to light up and multiple gauges malfunction, then the issue probably lies in the instrument cluster itself.
AA1Car.com points out that some cars run self-checks on their instrument clusters during ignition. During this self-check, all the indicators should light up, and any indicators that fail to come on may indicate an instrument cluster problem. Some cars make it possible to request a self-check by selecting certain display buttons.
According to AA1Car.com, most car manufacturers view the instrument cluster as a single component, so if even one indicator fails the repair shop must replace the entire unit. Although dashboard lights may prove replaceable by car owners, many of these lights now come built into the circuit board of the integrated instrument cluster.
AA1Car.com recommends disconnecting the car battery before attempting any kind of electrical system repairs. A connected battery could cause a short, leading to a fire, or cause the airbag system to deploy. Additionally, the Federal Truth in Mileage Act requires that in cars with an electronic odometer, the installer must either transfer the memory chip from the original instrument cluster or reset the new instrument cluster so that the car will display an accurate mileage reading.
