just installed a new head unit in my 4runner 2003 and I get no sound from the speakers, any suggestion?

 

just installed a new head unit in my 4runner 2003 and I get no sound from the speakers, any suggestion?

 

Did the speakers work before ??

Are the speakers even there??

Some sort of wiring mistake

There is a chance you have no audio output on your new unit

 

Did you connect the wires with actual connectors (harness, wire nuts, disconnects, posi-locks, etc.) or did you just twist the wires and tape? Its possible when you pushed the unit back in a connection caught on something and came undone.
Another thing is to cycle through your output modes on the unit itself and make sure the mute button is not active. Mine you cannot tell when it is muted or not other than not hearing anything.