Expert: Cleggsan - 3/9/2011

Question
I just bought a new Sony head unit. I hooked all the wires up correctly and when I idle, it works fine. but as soon as I accelerate it turns off. I thought it would be the ground wire so i attached a new one and that didn't work so i attached it to two separate ones and that didn't work. any answers?

Answer
It is not wired correctly. When you go off idle the voltage regulator kicks in and you are losing power to the head unit.  Double check the 12v wiring to the head unit.  You should have two 12v lines; one for constant power and the other remote turnon which somes from the ignition.  If there is a power amplifier between the head unit and the speakers it may be the remote wire to the amp that is cutting out.  Check that.

You can easily determine which 12v line is dropping out with a voltmeter.  You can buy a vom that is perfect for car system checking at Walmart or Home Depot for under $10.  Connect the vom gnd to a place on the metal chassis of the car somewhere and the red lead to one of the 12v connections on the unit.  When you accelerate you can watch the meter to see where you are losing voltage...

If you need more let me know.  But, please send model number of the head unit, make and year of the car and explanation of the entire audio system so I can know what you are dealing with.  Tks.