I have a Sony Head Unit and when I turn it up more than half way it shuts off! I have run all new speaker wires, I have unplugged the Subs, and tried un plugging one speaker at a time and three work fine but as soon as you put all four on it shuts off. When I mean shut's off it still has power just now sound.

Are you running a amp to said speakers that shut off or are they run off head unit? Also how old is the install? Have you ever had this problem before now ?

Your last speaker your connecting may be shorted. Try and conect the speakers in a different order to check. I had one that did the same thing in a car it was a sony too. You could have more than one bad speaker also. Im sure you have the polarity of the speakers correct?

I bet you have a bad battery

You have a dead speaker and your Sony head unit is not reading it properly.Find the dead speaker(s) and the problem is solved.The head unit is not the problem.

If your running the speakers on an amp try upgrading the power wire and adding a cap.

Ohm meter the speakers! Should be 4 ohms. Sony amp sections are real picky and shut off quick to shorts. Put a multimeter on it and I'm sure you will find a bad speaker or a short. If they all meter 4 ohms at the radio plug then its the radio but again I'm sure you will find it in the speakers or the wire.

First problem sony i'm an audio nut and have had nothing but problems with sony products over the years.

Okay
-No amp on speakers, just an amp for subs. When I by pass the Subs it still shuts off
-All the speakers are working when I check them individually. I can run any combination of three without an issue, but when I hook up the fourth no matter what order it will shut down.
-Hunster am I checking them right on the posts where I am connecting the speaker wire? Also are they 4ohms all the time or only at a certain sound level?
-Prostreeter you are right, I swapped out the head unit with a totally diff. head unit with the same wiring harness and it shut off....

THANKS for all of the help!!!