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Alternator? Battery? Hopefully not another GT350 electrical nightmare!

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Hey there! Against my better information, my 2018 GT350 got put away without a battery tender, driven only once monthly with a less than one year old low quality battery I sourced in Europe.
My buddy who is housing the car told me of electrical glitches, battery wouldn't hold charge, etc- no surprise, I knew I needed to get a AGM battery. Anyway, two different local shops have checked with a voltmeter and told him it's the alternator. Car has 19k miles. I bought a new battery (Odyssey Battery 96R-600). Friend learned alternator is 500$ part and it's buried, so hours of labor. Should I ask him to install new battery and drive/retest? I will of course get new alternator if required, but seems low miles for failure..
 

yotah1

Ford Employee
386
598
Detroit
My battery died last winter while in storage, after getting a "Charging System Service" message on the dash in October last year after an 8h drive. Suspecting the alternator is on its way out as well.

Mine is a 2017 GT350 with 25000 miles. I haven't had it checked by the shop yet but expecting the alternator to be the cause as I've put a new battery in and got that same message on the dash again a few days ago.
 
Trusted mechanic on a call told me the brain of the car detects failing battery and low voltage read is spurious; don't condemn/replace alternator before new battery install; car may possible need to "re-learn" (with OBD reader, maybe reprogram) to teach the electrical system that everything is ok after battery install. He thinks it is likely not the alternator- hope he is correct..
 
Trusted mechanic on a call told me the brain of the car detects failing battery and low voltage read is spurious; don't condemn/replace alternator before new battery install; car may possible need to "re-learn" (with OBD reader, maybe reprogram) to teach the electrical system that everything is ok after battery install. He thinks it is likely not the alternator- hope he is correct..
Neew battery didn't solve problem. New alternator did. No fried wire harness or other explanation. Nice when all the electrons go where they should!
 

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