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Discussion Starter #1
My 01 mustang is acting up TERRIBLY. I went through a phase about five months ago where the battery kept dying- turned out to be the alternator so we got a brand new one, the shop tested it, and it is good. not faulty.

then about two months ago when i thought the problem was solved, more batteries started dying w/no explanations...I don't know if this information is relevant, but I started spotting signs of when the next battery was about to die. I.e. the cd player started acting up, clicking when trying to changed disks. the bass at one point in the speakers would die out. but once the battery was changed, those signs disappeared and would later come back to "remind me" of getting a new battery soon.

then the problem suspiciously "solved itself". The car acted fine, no problems at all for the last two months until one morning car was dead. no clicking when trying to start it like it used to. just nothing. i had to charge the battery three times in one day at one point. something is REALLY draining it. it's been in a shop since last friday, but they have yet to identify the problem. They said they know there's a shortage of some kind somewhere, but it is being intermittent. meaning it only acts up when no one is looking so no one can find the problem!! ahhhH!!!

my question to y'all is has anyone had any similar issues? if so what was it? ANY INFORMATION AT ALL PLEASE it would help so much. suggestions, comments, etc. I NEED A RELIABLE CAR SOON!
 

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Discussion Starter #3
OK, some more info.

After 3 weeks at an auto electrical specialty shop, they had no definite answers.

They said that twice the problem occurred, but it ran the battery completely dead...zero volts. In order to diagnose the problem, they had to charge the battery, and as soon as they began the charging process the problem went away.

The only guess they had was what they called the "main relay"...I assume they meant the PCM. They said they "heard clicking from the main relay in the fender when they began the charging process." Does this make any sense to anyone?
 

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Do you plan on fixing this yourself? Parasitic draws are some of the hardest problems to track down. But unless you are prepared to systematicly attack this, it will likely be elusive.

An amp meter installed on the battery negative is required. Clamp on style is easier. Shut type is cheaper. Turn off all devices. Pull the dome light and the other courtesy lights. Record the amp draw. Pull the fuses one at a time from the central junction box (BJB) and record the amount that the amp draw drops. Some of the fuses will drop more than others. Post the results.

Skip F2.21.

FWIIW if there are any after market sound systems are installed, the search should start with these.
 

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Discussion Starter #5
I guess we will have to fix this ourselves, an electrical specialty shop couldn't.

We know about tracking draw-down issues, but we can't track something that's not always there. The problem just appears randomly.
 

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Discussion Starter #6
OK, now we have more to go on...

Tonight the problem appeared and we were able to determine that pulling the fuse #6 under the hood causes the battery draw to stop. That's the sixth fuse from the engine in the middle row, 40A.

The diagrams I could find says this fuse runs "Ignition switch/PCM". Has anyone seen this before, what was the fix, is there more diagnosis I need to do? TIA.
 

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IMO, starting with the battey junction box (BJB) is a not the best idea. Each fuse controls why too much to be useful.

Start with the Central Junction Box (CJB).

As a reminder, the draw will never be zero. There are systems in the PCM and GEM that need stand-by power.
 

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Discussion Starter #8
OK,thanks. So I have now tested using the CJB. After pulling one fuse at a time and observing my test light (sorry, I blew up my multimeter at the beginning of these tests) I have noticed about a 1/4 drop in light intensity when pulling fuse F.27 which controls "Radio (18806)". This car still has the factory radio/CD changer combination.

To review, when I pull fuse F1.6 my test light almost goes out (I would guess a 90% drop in intensity). F1.6 controls "Electronic flasher module, Radio (18806), Subwoofer amplifier, front, Subwoofer amplifier, rear".

For the moment I have pulled fuse F2.27, but my test light is still quite bright. What should I test next? I looked, and there is no fuse in F2.9 ("Subwoofer amplifier, front, Subwoofer amplifier, rear").

Thanks again for any help...
 

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IMO, this problem is going to be 10x harder to solve if you are not using a reasonably accurate AMP meter. The method used does not tell how much current is being drawn by the various circuits.

The fact that your method already points to a big user being the "sound" system related should raise red flags.

Do the sub amps use the DB signal wire for remote turn on? Have you checked to see if there is stray voltage or ground fault on the DB wire?
 

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Discussion Starter #10
There are no sub amps; that's why I said there is no fuse F2.9.

I should be getting a new meter in the next few days.
 

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Discussion Starter #11
OK, new meter says:

With all fuses installed, a draw of 2.0 Amps :nono:

Removed fuse under hood (as mentioned earlier), draw of 2.1 mA.

Reinstalled under hood fuse, removed radio fuse under dash, draw of 2.1 mA.

So its seems obvious that the factory radio/CD changer is the culprit. For now we are driving the car around with the under dash radio fuse pulled.

Thanks for the help!
 

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I think I am having the same problem. I have a 2001 Mustang V6 and the battery continues to lose charge but the alternator checks out okay. The radio has acted strangley a few times. Did you ever get your problem solved or are you continuing to operate the car with the radio fuse pulled?
 
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