alright my mom had some trouble the other day, this is what she said happend....
the engine was off and she pushed the odometer reset button. she said all the lights and symbols on the display lit up and when she turned the engine on they went off. but now the speedo and tach dont respond. anyone know what this could be??? much thanks

 

If the ignition switch is in the "on" or "acc" position and you hold the trip reset button in, the computer does a light and sensor check for the dash. I don't know if starting the engine in the middle of the test will cause a problem like you are having or not. You might want to rerun the test again and see it the corrects the problem.