car stereo wiring
If this stereo is used I would suggest taking it out and testing it. If you have 2 sets of wires then its a 2 channel radio. Which isnt uncommon for older tape decks
Solid Grey= Positive Hook to positive terminal on Speaker
Grey/tracer = negative Hook to negative on terminal.
If you have a car battery you can check this and make sure the outputs arent blown on the radio its not uncommen. Since people often used the 2 channel to run 4 speakers thus dropping the Ohm load and just simply not enough power. Just need some wire aligator clips and a speaker. If it works then its good. If not then the outputs are blown.