HiCustomer welcome to Just Answer!.
If you're seeing intermittent operation from the radio, it may be the radio itself that's causing your problems. You'll just need to verify a pair of power feeds to the unit first to verify it one way or the other.
Either radio (standard or premium) is powered through the same two sources, simplifying things somewhat. Both fuses are inside the left end of the dash, at the Junction Block.
Fuse 17 is your constant battery
feed to the unit, something used to retain system memory when shut off at the key. I didn't trace the circuit completely, but this fuse may also be called the IOD (ignition off draw) fuse, which will also supply locations such as the cigar lighter and interior lighting. If this fuse is blown, the majority of the time it will have something to do with the cigar lighter element or an electrical accessory plugged into the receptacle. This fuse may also be encased in a black plastic holder, requiring that the hinged top be unclipped and rotated back for access. It's a 15-amp circuit.
Fuse 7 is your switched feed, coming directly from the ignition switch which also has to be considered in the repair if you fail to see power at either end of this fuse with the key on. It's also a 15-amp circuit.
The only ground shown for either radio either bolts onto the case or plugs on separately but requires the unit be removed for testing.
If all powers and grounds are present, yet the radio won't wake up... that's when the trail goes cold and it will have to be sent out for repair or exchange.