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Offline Blue79Pinto

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Overnight Battery Drain
« on: May 02, 2013, 11:15:37 PM »
The battery in the car is brand new.  I have replaced the voltage regulator as of two years ago.  I never have replaced the alternator though.  At idle the brand new batter reads 11.5v to 12v depending.  Is this a sign of a bad alternator?  I have put a modern stereo which may be part of the drain, but I am going to equip it with a toggle switch to completely turn it off so it cannot get power when the car is on.  By the way forgot to mention this brand new battery died overnight while in the car.  And after only a few hours of being in it after being charged and run it went down to 10.5V. Any help would be much appreciated.

Offline sedandelivery

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Re: Overnight Battery Drain
« Reply #1 on: May 03, 2013, 05:26:57 AM »
We have a 1984 Ford F350 dump that had a similar problem, and the alternator ended up being the problem. However the F350 has a built in voltage regulator which the Pinto has an external one.

Offline Blue79Pinto

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Re: Overnight Battery Drain
« Reply #2 on: May 03, 2013, 10:30:14 AM »
So I had the alternator tested and it wasn't the problem.  Suggestions?

Offline HOSS429

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Re: Overnight Battery Drain
« Reply #3 on: May 03, 2013, 11:36:10 AM »
 unhook the negative battery cable ..  hook up a test lite between the cable end and the battery terminal .. the test lite should glow if you have a short somewhere or something still hot with juice ,, start unpluging fuses as you watch the test lite .. if it goes out with a specific fuse then that fuse most likely controls whatever is draining your battery .. if no fuses find the problem then  go to unpluging any and all other plugs you can find .. one of the most difficult shorts for me to find one time was a defective door lite switch .. it stayed hot with the door shut or open but didn`t turn on the dome lite ...

Offline Blue79Pinto

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Re: Overnight Battery Drain
« Reply #4 on: May 03, 2013, 02:07:38 PM »
So far none of the fuses did anything, so I unplugged the stereo just to make sure.  It wasn't that.  I also unplugged the voltage regulator and the alternator just to be sure.  It wasn't those either.  This is rather annoying haha.

Offline Blue79Pinto

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Re: Overnight Battery Drain
« Reply #5 on: May 03, 2013, 03:49:44 PM »
So I finally found it.  It's one of the wires that controls the dome light coming on when the door is opened and closed.  HOSS429 it's the same problem you had.  How did you fix yours?

Offline HOSS429

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Re: Overnight Battery Drain
« Reply #6 on: May 04, 2013, 08:06:53 AM »
so long ago .. i`m certain i simply put another door switch on .. you know your head lite switch can also turn on your dome lite dont you .. may be as simple as turning the knob off ..

Offline Blue79Pinto

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Re: Overnight Battery Drain
« Reply #7 on: May 04, 2013, 10:15:01 AM »
As it turns out it was just my done light.  Not the switch.  It was shorting out and the wire I unplugged operated the dome light.  So I no longer have a short, but I don't have a dome light either.

Offline HOSS429

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Re: Overnight Battery Drain
« Reply #8 on: May 04, 2013, 10:54:36 AM »
well .. now you have something to fix .. i always liked a problem to solve now and then ...