car battery, ford taurus, battery cables

hi,

i bought a 2000 ford taurus lx 3 years ago.  the alternator nor the battery has never been changed since i bought it.  as i was driving today, every time i turned the car on, the battery light would flicker and go off, and just now, it's flickering as i drive and the lights are dimming on the dashboard, but then come back to normal when i turn off the heater and drive 40 mph instead of 60 mph.  am i to assume the battery is dieing, or the alterator? thank you.

Answer
    The alternators used in these cars are pretty reliable, but yours is 10 years old.  The symptoms you are describing make me think it's the alternator getting ready to go bad.  It could also be a bad connection with one of the main power wires or the battery cables.  If the charging system were not working at all, then your battery would get too low to crank the engine.  Since you're driving the car, I'd guess that's not the case.  Get it fixed soon or the battery will go flat, and that severely shortens the life of the battery.
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