1991 Dodge Shadow No Speedometer or Tach

Computer problem
1991 Dodge Shadow 4 cyl Front Wheel Drive Automatic

The speedometer hasn't worked for some time now. A new distance sensor failed to fix the problem. Now, the Tach has stopped. Over a three day period, it would work iat times and then just stopped.

I subscribed to Eautorepair and looked for a Tachometer test procedure. I followed the instructions:

Battery Voltage to proper cavity
Continuity to ground at Cavity F
Tach signal from computer (sbec) at cavity H was 2 volts. The instructions said to have at least one volt.

Zero Ohm from pin 43 of computer to cavity H = good continuity in signal wire.

With the help of a local salvage yard, I replaced the Tach drive module three times, the tachometer assembly twice, tried another complete cluster assembly with negative results, and tried a computer out of a 91 Dodge Spirit (salvage yard said it was compatable). Still nothing.

The car starts up fine and the small gauges all work.

Please Help!