Car Stereos: sound with fm/am, but none with cd/dvd

Question
I just installed the JVC KD-AVX44 in my e36 BMW. The sound works in FM/AM as does the video in DVD mode. However, there is no sound in CD or DVD mode. I thought maybe there was some setting but I've browsed and changed all I could think of. JVC says I must've installed it incorrectly. Because the sound does work in AM/FM, I think it must be something else. I've already replaced the unit once when I thought it was defective.

Answer
Hi Arnold,

I read your explanation as to what fixed it -- that's the weirdest wiring I've ever heard of in a deck.

Remind me never to buy JVC. :)

Happy to hear you got it working.

Justin