first, remove the instrumentation gauge from ur dashboard, then look at its back portion which you will see some circuitries... use a tester either digital or not or which one you are comfortable you use with.. check its connections if it is working, if not you can use soldering iron for its loose connections but, if u have a budget for that you can score some in surplus shops near you... before anything else i would like to add that maybe some of the sensors of the gauge are not already functioning since the model of your car is almost a decade