Make sure you have proper voltage on both the red and yellow wires in the main wiring harness to the back of the radio. Car stereos have two 12-volt inputs. If only one is connected, you can get unexpected results. If you have voltage (12v+) on these two wires and the radio has ground, then unplug it and reconnect. If it still doesn't work, the radio is toast.
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Make sure you have proper voltage on both the red and yellow wires in the main wiring harness to the back of the radio. Car stereos have two 12-volt inputs. If only one is connected, you can get unexpected results. If you have voltage (12v+) on these two wires and the radio has ground, then unplug it and reconnect. If it still doesn't work, the radio is toast.