Why is my Sony head unit's amp output only work for radio and not aux?

I have a Sony HU gt250. When I listen to the radio, the sub works fine, but when I use Aux, the sub does not work at all. I have tried a different cable and source. Any help would be appreciated.


Thanks.|||you are using the wrong turn on lead on your radio.you are using the power antenna lead instead of the amplifier turn on lead.it is easy to do,one wire is blue and the other is blue with a white stripe.