1992 Explorer Audio Systems
Looking at the photos from "Crankcase" -
the gray connector on the right is the radio "Power" connector - the same connector is used in "standard" and "Premium" systems (though the pinouts are different).
The black connector on the left is the "Speaker" connector. The one shown is for "Standard" sound systems ONLY, the Premium Sound System or Ford/JBL system does not use this connector.
The Premium Sound System and Ford/JBL System use the small "squarish" shielded connector (with 8 pins) attached to a gray shielded cable.
The cassette radio in the factory "Standard" system has a base part number of -19B132-; the part number for the Premium Cassette radio, used with Premium Sound, or Ford/JBL, would have a base part number of -19B165-.
The Ford Premium Sound System will have one (4 channel) amp in the RR qtr trim area; the Ford/JBL System will have TWO amps (one 4 channel, one SW) mounted to the SW enclosure in the RR qtr trim.
If you have an Explorer with the shielded connector, and a -19B132- radio, somebody has changed it - would be really hard to tell what or how they did it without pulling out all of the wiring.
Hope that helps you sort out what you've got.
Regards,
cobrajeff