Jensen VM9020TS Car DVD Player "hooked amps sub amp wont" Questions

hooked to the atenna power wire on the radio the power wire to the amp needs to go to the BATT. with a fuse make sure your amp is grounded well and less than 18 in. then check your RCA wires after all

...amps and a 12" sub hooked to the radio and the radio mode works fine but when i play it in cd mode, the sub and the back speakers wont play only the front door speakers, which are the only speakers ...

...hooked up my aftermarket subs and amp, you can hear the bass of the songs on the cd but nothing from the speakers. everything works fine with an ipod and on tuner. cd issue was the same before subs ...