I bought a new CD Player/Radio Tuner for my Nissan 240SX. Earlier there was a Sony CD Player which got stollen.
After making the connections, Radio/CD player light comes on but no sound from any of the speakers. I took an external speaker from my music system and connected it to CD Player leaving every other wiring intact. I could hear CD playing.
So I see the problem is with Speaker wiring from the Dash board to actual speakers.
How to figure out which wire is connected to the speaker. Any easy way other than opening the side panels.