Are you able to remove the radio from the dash? That way you could check if power is going to the radio by disconnecting the wiring harness plug and sticking your voltmeter probe into the hot wire port on the harness, usually red or black. On my rig the radio has 4 small holes on the front panel, one on each corner. If you put a stiff wire in the holes it unhooks a clip and the radio slides out for repairs or replacement. There is a thread on this site. If the power and ground connections show good then the radio is defective.
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