My 1999 mercury grand Marquis us killing my battery. So is it the battery or the alternate?
Asked by PaulieApril Jul 27, 2014 at 01:19 PM about the 1999 Mercury Grand Marquis 4 Dr LS Sedan
Question type: Maintenance & Repair
2 Answers
Test alternator output voltage. It should be 14.5 volts or so. If not it's probably bad. Does it drain down while driving or when it sits overnight? If while driving check alternator and battery connections. If overnight test for parasitic draw.
www.youtube.com/watch?v=zdIKNnwEjIs -- this is how to do the draw test.
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