Upshift Indicator

The upshift indicator gives an indication to the vehicle operator when the manual transmission should be shifted to the next highest gear in order to achieve the best fuel economy. This indicator is controlled by a transistor on the instrument cluster electronic circuit board based upon cluster programming and electronic messages received by the cluster from the PCM over the PCI data bus. The upshift indicator function of the instrument cluster is electronically enabled or disabled by a PCI data bus message received by the cluster from the PCM. The upshift indicator LED receives battery current on the instrument cluster electronic circuit board through the fused ignition switch output (run-start) circuit whenever the ignition switch is in the ON or START positions. The indicator will always be OFF when the ignition switch is in any position except ON or START. The LED only illuminates when it is provided a path to ground by the instrument cluster transistor. The instrument cluster will turn on the upshift indicator for the following reasons: upshift lamp-on message, and actuator test.