Anybody know about sony head units? Mine won't turn on.

[gt1009]

I'm switching from an old sony 4000 to a new sony 250. The wiring harnesses look exactly the same, and everything hooks up to the new head unit. I plug the thing in though and the new head unit won't turn on. I have power at the red wire on the harness, but when I plug the head unit in nothing happens.

 

[mrwilliamsburg33]

Do you have a yellow wire? Thats usually the main power source wire...

 

[gt1009]

I'll check that one and see what's goin on with it. I have no idea how it is wired now as I didn't do the last wiring, so it could be to the point where if that doesn't work I'm just gonna rewire the whole power setup straight to the battery.

 

[AJMBLAZER]

Do the wires on the plugs look the same?

As in the same colors going to the same points on the plugs for the 250 vs 4000.

 

[mrwilliamsburg33]

Also a good point... Your leads would have to match up pin to pin... If they are off nothing will work right. The plugs themselves could match up but the wires inside the plugs could be off.

There might be a little inline fuse (should be anyways) in the power lead... that could be blown or not making good contact. There is also a fuse on the back of the head units themselves... check that one too

Do the wires on the plugs look the same?

As in the same colors going to the same points on the plugs for the 250 vs 4000.

 

[Jessie James]

If you did not do the last hookup then you should test that the power line actually has 12v when the ignition is on and when the "accessory" position is on (if your truck has that).

As mentioned, compare the new harness to the old one. Just because it's the same design does not mean it's the same wiring setup. You could be sending 12v into a speaker terminal for all you know.

When all else fails, read the manual!

 

[dhcomp]

Harnesses should be the same. Check power to the harness with a multimeter.

Check fuse in back of radio if harness power is good.

Push the little reset button on the front with a paperclip....sometimes fixes problems.

GOod luck!

 

[Stomis]

Sony has had he same harness for nearly 20 years. I think in the early 90s the cassette decks had some that had 2 more pins but after that it went universal. I'd first poke the harness unplugged from the radio with a test light.

If you had the key on when you plugged it in you may have blown your regular radio fuse in your truck if it arched.

 

[gt1009]

Ya, all the wires on the harness go to the same spots. I tried to find that little reset button but I couldn't? I guess mine doesn't have one but I'll check that yellow wire when I get back from work today.

 

[Stomis]

Poke the harness like I said. If its got power on the yellow wire than either

The fuse is blown in the back of the radio, the face plate has a bad connection or its fried

 

[Blue85]

I'm not familiar with those units, but make sure there is a ground connection. Sometimes installers just let it ground through the chassis. When you plug in a radio not screwed to the dash steel you get nothin'.

 

[Lotsa_Faith]

Make sure you're getting 12 volts to the red AND yellow wire...I took two sony head units back to Best Buy last month b/c they wouldn't work for the life of me, only to finally find out my yellow wire was only getting 6 volts. Found a new constant on the fuse box and tapped in, problem solved!