The Performance Shift on my 99' GTP works great while its in use. I can tell the difference between on and off, but my problem is the "PERF SHIFT" light in the inst. cluster doesnt work anymore and the "PERFROMANCE SHIFT" display in the DIC has not worked in 8 years. I have done a bulb check in the inst. cluster and I have replaced the DIC...could this be a wiring problem? Or maybe a bad shifter knob?