1999 Ford Taurus Battery goes dead unless I unhook it

1999 FORD TAURUS
140,000 MILES • 6 CYL • AWD • AUTOMATIC
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SHEL07
  • MEMBER
  • 1 POST
MY battry goes dead everynight unless I unhook the positive cable, everything is off in the car. I bought a new battry so that's not the problem, I had the alternator tested and they said it was fine. also, my dash lights and tail light have stopped working all the fuses are fine. Any help would be great.
Feb 27, 2008 at 5:36 AM
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MERLIN2021
  • ✓ASE Certified Mechanic
  • 17,250 POSTS
  • ASE Certified Mechanic
Get an analog voltmeter remove the negative battery cable, attach the Black lead to the battery post, Red lead to cable end, then pull fuses one at a time, make sure there are no accessories or lights in the on position, Key off! Close the door after each fuse and check meter, when you pull the fuse for the bad curcuit, the meter will drop to 1 volt or so. Check all fuses, even under the hood. If meter does not drop, remove the battery connection from the alternator, if it drops now, the diodes are bad in the alternator. Put the fuse back in were it goes as you go so you don't forget which fuse goes were!
I would start with the lights fuses...
Feb 27, 2008 at 7:59 AM
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