Before anyone can give you good advice, you need to post the year and model of you car.
Along with that, we need a list of modifications or additions like external tach or gages.
Is this a stock radio or aftermarket? Does the lighting for the radio work OK?
My dash lights didnt work and i found out the aftermarket stereo is to blame. Unplugged the wire harness from stereo and works fine, that fixed many issues i had with my wiring.