4 wire cassette radio?
 

Got this for 10 bucks, said it worked. Any ideas on how to wire it?

Re: 4 wire cassette radio?
 

I believe red is battery +
Black would be ground 12 volt Negative for speakers as well as radio ground
grey is front speaker +
green rear speaker +
long black plug is for antenna cable end

i hope this is right give it a shot
i am sure others will chime in
you could also put this in the truck audio section