You need to review the audio setting! Check the cables behind device, (audio one) then make sure it is connected with proper one on the plastic connector! Good luck
While the machine is on, put the old toner back into the machine, close the front cover. Open the front cover and replace it with the new toner. Make sure new toner is shake well.
I need more info. Did you check the ground wire to make sure you have a good ground? Some installers try to rely on the antenna for a ground when hooking it up due to laziness and it will eventually burn the stereo out from low voltage, or, you could have amps that are killing the battery enough to drop the voltage down and it's killing the stereo. I have also seen ground loops kill stereos, but, I need a bit clearer info as to exactly whats happening to answer the question.
