Audio Systems: car stero, peugeot 306, car stero

Question
I have a standard head unit for my 1995 peugeot 306.I have used a vol meter for 12v and gives me full power. But my head unit will not turn on???? do you have a possible solution???

Answer
It probably has two 12v lines.  One is power to the unit all the time; constant 12v to keep the preset memories, clock, etc. alive.

The second 12v line is from the ignition to switch the unit on when the key goes ON.  

Therefore, check both 12v lines and the ground; this will make sure the unit is getting all power it needs.

C