I don’t know if you managed to sort your problem out but if not then here’s a few things to look out for.
If your stereo is DAB then try an FM or an AM channel & see if you get any static sound from the speakers. ie not tuned in correctly. If you don’t, then go through all of the audio settings on the stereo & make sure it is not in ‘MUTE’ or the Auto Volume is not set too low.[br]
Also check the Balance & Fader settings. Try adjusting the Fader to the front speakers only & see if that makes any difference. If not then try the rear speakers via the fader. It maybe someone has wired the speakers up incorrectly via the Fader settings. Sometimes the radio works separately to an AUX input or CD player.
Because you said you get sound from the CD & the Aux input, i would say 100% it was something to do with the radio’s audio settings.
Hope this helps.
Gazza