not sure if that ground wire has anything to do with the radio, and the radio fuse would be blowing everytime if it did, (seems to me).

question: can you dim the lights of the radio with the headlights switch dimmer?

I also don't understand why you have lights but no sound. Does the display work in radio mode? can you select radio stations?

try to insert a cassette tape to see if it plays and sounds?

if the cassette runs, and the radio display works, the problem is in the speakers wiring.

 

@92aeroXLT, I've only got 3 myself and the wife says no to any more. I've noticed in the last couple of years they're getting much harder to find. I hardly see anything on Craig's List anymore and the ones that do show up are rust buckets.

 

 

here's the rear of the 1997 radio, I think they are all the same plugs, but I do not know if the wiring positions is similar.

 

 

The quick solution is to donate them to the Aerostar museum in your local town, then get the tax write-off.
Or perhaps the Smithsonian would be interested.
*******
Good thread.
Motivated me to pencil in an audio project and grab "The Last One!!!!" of these off of eBay.
This one seems to nicely walk that chasm between the WAY obsolete cassettes and WAY too modern buttons.
Got my rotary volume **** back, and I can read the button labels, but I'm now stuck with WAY obsolete CD's.
Just hope the lights and sound work.