CD player power, no sound have the right connections but..

yea just install a pioneer cd player and power kicks on but no sound, work in my friends car just fine. i have the right connections is that for some reason theres no sound… speakers are not blown and fuse are all good, powers on, it reads… but like i said no sound any suggestions… help this is my girls car and she all mad now because she has no music =)

check to make sure no speaker leads are shorting to ground. the newwer head unit have built in protection so if anything shorts it shuts off.