Turned the ignition on the other day and turned the radio on - I got sound through for around 2 seconds then it immediately faded out to no sound at all. Same thing happens when I play a CD but I have to turn the ignition off and back on again to replicate the problem.

I've checked the fuses for both the radio and amplifier (they hadn't blown) and even replaced them but no change

Anyone had any similar experiences or know what it could be?