stereo question

ok i have a 99 malibu just got it and tried to install an after market stereo and it powered up but no sound unhooked it and put the old one back in and sound can anyone tell me why it will not put out any sound when i install an aftermarket stereo please

ok i have a 99 malibu just got it and tried to install an after market stereo and it powered up but no sound unhooked it and put the old one back in and sound can anyone tell me why it will not put out any sound when i install an aftermarket stereo please

from my understanding ur supposed to get that crazy wire harness so u can leave ur factory radio hooked up at the same time as ur aftermarket because of some theft deterrent crap in the radio

does the car have factory amps? if so, maybe u need to find the trigger wire for them or bypass the whole shit and run new speaker wire