CD Changer, static?

Hello. I am stuck on something.

My girlfriend's car  has a JVC arsenal head unit and a JVC 12 disc CD changer.In the last week it has started having a problem. This setup has been working fine for a year and nothing has been changed on the car.

Headunit is powering Alpine Type S coaxials. No amp, etc.

FM and CD in the head unit = sounds fineCD Changer = sound on the front left and rear left speakers are extremely low and have A LOT of crackle and static.

All connections appear tight. Head unit seems to be working fine. CD changer functions fine.

Any ideas where to start at trying to fix this problem?

Thanks!Steven

anyone................................