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04 ZX3 SVT Sonic Blue - 137k
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Discussion Starter · #1 ·
Hi all,
New to the SVT and to the forum. Thank you for having me, and let me know if I make an error in posting.

I got a very clean single owner 04 svt yesterday (23/Nov/21), and it is a peach.

When I got it, the aftermarket sub/amp had removed by the previous owner, and the head unit he installed wouldn't power on. I checked his connections with diagrams posted in another thread, and they were sloppy but okay. I replaced the fuse on the head unit and redid some of his wiring.
However, no connections were made to the factory sub/wheel control connector, so I made a harness using some extra coax and fed the factory sw preamp to the head unit, and ran the amp enable to a keyed power source. I also connected the shielding of the cables to the shielded factory wire.
When I put my thumbs on the coax, I could hear a buzz in the sub. (It was getting power) I then put volume very low (trying to avoid a lot of power shorting something) on the head unit and connected things one by one to make sure they worked. All four front speakers worked fine, but I accidentally dragged the subwoofer coax core against the shielding ring on the head unit, and saw a couple small sparks. After all the connections were made, the subwoofer is inoperative.
I heard no popping out of the sub when this happened, and I double checked my connections. I will go over it again tomorrow, as it isn't as nice as I would like. I verified that I had power going to the amp enable and constant power to the sub. However, I found 12v all over, so I am wondering if there is a bad path to ground.
I did crack the casing on the amp open in search of an internal fuse, and I see no burnt terminals. The board is spotless.
I then found out that there is a 30A fuse in the engine bay that leads to SW. It was intact. When I remove it/replace it with power on, there are small sparks indicating that there is power getting across the fuse.

I am wondering a couple of things:
Could I have fried that amp in my stupidity, when I dragged signal across shielding terminal?
Does anyone have information about wires going to/from the amp itself? I find 12v all over the place on the amp connector, and only 1 (or 2?) with ground potential.
Is there another fuse that helps that amp fire?
And is it possible that my selection of keyed power rather than the head unit sub enable is having an effect?

Any information is greatly appreciated!

As a side note, I plan on building an MDF sub box with stealthy amp install in the future. I want to keep it fairly low power (100w rms) to keep the sound signature balanced. I am certain that a 2004 factory sub is past its prime by now, and even with the same power and a better sub, it would sound much better. I want to keep it fairly stealthy and preserve trunk space.
For now, funding is limited as I am a broke college kid. When that project comes to fruition, I will post dimensions and parts selection.
 

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2013 Focus SE gray 5 spd hatch
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1,519 Posts
I would guess that you fried the amp. Factory amps are not great anyway but if you go with an aftermarket one you should/may have to run new all new wiring because of Ford's tendency to wire premium stereos very strangely and not to industry standards.
 

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04 ZX3 SVT Sonic Blue - 137k
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5 Posts
Discussion Starter · #3 ·
Thank you sir, I redid all the wiring with solder and double-checked connections, and still the amp isn't even coming on. Unless there's a disconnected ground the only other thing it can be is the amp.
 
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