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Discussion Starter #1
Hi guys:
I've had an intermittent electrical problem for about a year now. It took 6 months in between the first two occurrences, but lately it's been once a month or more... I've tried to be as descriptive and detailed as I can about the problem (let me know if I left something out). Hardest part is I can't seem to find anything that makes the symptoms repeat. :/

Info about my car:
-2003 Focus SVT
-130k miles

The only aftermarket electronics I've installed are a headunit and a subwoofer. All sound system components were installed well before the problem began.

Symptoms:
-Car begins to stutter. Sudden loss of power for a split second. I can't usually hear any difference from the engine like misfiring or something would create. I can only feel it through the accelerator.
-Dash lights start flashing and dials start randomly taching over (like when you reset your ECU). My dome light also flashes (I only noticed this because it happened once at night).
-Also at this time, my radar detector gives high voltage warnings.
-Car begins losing a lot of power and the difference is audible. I am forced to pull off the road.
-After shutting the motor off, the car will not restart immediately. My radar detector now gives a low voltage reading. Also at this time, the starter does not turn over and there is no other noise from the engine.
-If I wait 2-3 minutes, it will start up and run as if nothing has happened.

I'm not sure what the problem might be or where to start here. I've taken it to the local Ford dealership, and they refused to help me unless the problem happened every time I drive it. Hoping real experts on here can help me out! :)
 

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Old Phart
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Couple lines of thought.

First I thought of the rear hatch umbilical, because many of the initial symptoms match what shorts back there can do.

Then, started wondering about the alternator & it's connections. Check out the "pigtail" wiring connector to it for issues first. Then I'd hook up a voltmeter to try & catch what's happening the next time the problem pops up for more information.
 

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Discussion Starter #3
I was thinking the alternator as well since the whole electrical system seems to be effected. Also, the fact that it's gotten worse with time makes me lean toward the alternator. The last time it happened I was playing music and when I turned the music off, the symptoms were less severe. I think that points to the alternator as well. Thanks for the advice!
 

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Old Phart
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Semi-complex system with PCM control/sensing of the alternator.

That plug is key, and wiring/connector have been known to fail. Replacement "pigtail" for repair is avail. if needed.

All interrelated now, the PCM looks at charging levels to adjust the IAC for load at idle & cuts out the alt. load at full throttle. The rest of the time it's just keeping control of charging voltage based on the sensor wire.

Not saying the alt. itself may not have a problem, but you don't want to go to the effort of getting that out for testing/rebuild without checking everything connected to it.
 

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Discussion Starter #5
Hmm ok, I'll see if I test those things before messing with the alternator. You think the rear hatch could still be the issue? I've never checked it before, but I know the hatch gets rattled around quite a bit by my sub. Lol not sure if that would cause a problem back there...
 

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Old Phart
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Lights & odd electrical can be a result of the hatch umbilical problem, some great pictures of damaged wires in older threads on that here.

Wouldn't do the high voltage though, that's where the alternator questions come in.
 

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Discussion Starter #7
I was just checking PCM/alternator symptoms and that sounds like my problem. I'll get it checked out Monday or Tuesday and report back!
 

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Discussion Starter #8
Took my car to the mechanics today, and they diagnosed the alternator as suspected. I told them to check the wiring as well, and they came back and said it was fine. Sooo now to go buy the parts and tools to fix it! Thanks for the help diagnosing! :)
 
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