The other day I had a friend of mine install my Kenwood car stereo in my 2000 Monte Carlo, and once he installed it and turn it on to see it worked there was no sound. He wired it right and everything no fuses blown, what can the problem be. Need help ASAP can't live without my radio in my car

 

Was the factory amp bypassed when the new head unit was installed? IIRC you need to in order to get the speakers to work.