Why the battery starts dying while vehicle is running??
A fried of mine has a 1998 Ford expedition with 5.4 l v8, battery was checked
and charged at advance auto and also alternator was also bench tested,
reinstalled and started right up, but within 30 minutes had to jump start vehicle
again, had to do it several times just to get it back home, what would be the
problem, tired of paying repairs, still has same problem.
That rig has a computer controlled charging system, so if the battery and alternator both checked good then the problem could be in the computer or the wiring itself. I recommend taking it to a shop you trust and have it scanned for trouble codes and wiring issues.
IF ITS ACTING UP LIKE A BAD ALT I WOULD CK THE AC COMPRESSOR AS AT TIME WHEN THE AC COMPRESSOR ENGAGE IT PULL TO MANY AMPS ACTS LIKE A BAD ALTERNATOR ...BUT IT DOESNT MEAN YOU DONT HAVE A BAD ALTERNATOR AFTER 30MIN OF DRIVING THATS WHEN THE VOLTAGE REGLATOR BREAKS DOWN ...I WOULD HAVE TO SAY U HAVE BAD ALTERNATOR .
The AC is not working, next project as soon as I can fix the battery dying issue
Also after starting there is a slow beeping sound coming from passenger side dash separate from normal starting chime.
That could be caused by voltage, low power can cause all kinds of weird problems on these newer computer controlled vehicles. I would still get it checked before it starts causing other systems to fail.
aah theres the culprit beep on passenger side i bet the car have sunroof ....on the right side there a fuse box i bet if you pull it you would find water damage in that fuse box very common on expedition and navigator....
You may have a bad battery, may be that a cell is shorted out.
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