I didn't see an aux-input on that Continental, unless it's under the cover labeled 'USB'.
In my '96 Tacoma, I replaced the PO's DOA Sony CD-radio with a newer Sony unit from 'Pick-N-Pull'. It works fine, but I don't always want to hear CDs. So it's nice it has an aux-input to plug in my MP3 or Sony Walkman cassette player.

As to fixing a dead cassette-deck, often it's a rubber belt. A few years ago, I was able to order a belt from Becker for the vintage Europa cassette-radio in my '84 TD.
If you can't find and install a replacement belt, depending on your cassette's auto shut-off system, you might be able to use one of those cassette adapters to connect an external player.

Happy Motoring, Mark

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DrDKW