TrevinE

I am trying to troubleshoot a tach and speedo issue with a 1990 IROC convertible.

At first, my tach was reading but seemed a bit jumpy and at a glance seemed to be reading high. The speedometer was the real problem as it was working but intermittently. the mileage counter as well would roll forward only when the speedometer gauge was working.

I changed the piece that goes into the transission as well as the plug and that didn't help anything.

After researching and talking to some folks I then changed out the ribbon circuit on the back of the gauge cluster.

Now all light and gauges work EXCEPT for the speedo and tach. Neither one of them work at all. Not even intermittent.

Any of you guys have any thoughts or ideas? i am not sure where to look from here. Is there maybe a control box or module of some sort between the transmission/ignition and the gauges themselves that might be bad causing the signal to not get to the gauges?

Any help is greatly appreciated.

Thanks

TrevinE

Anyone? Bueller?