Alt. BAD or WEAK?
Lead Driver
Joined: Jan 2005
Posts: 7,782
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From: Huntington Indiana
Try this - take off the + battery cable overnight. If it starts right off then you do have a short in the system , if it doesn't the battery is bad. Then the fun starts (trying to isolate it).
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If you are going to play with it to night, do take off the pos cable and just touch it to the terminal (make sure all power accessories are off including dome light) you should only see a very small spark (due to the under hood light) if the spark is pretty big, you probably have a short somewhere.
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if my last post is not the case, get a volt meter and do the following tests: check voltage at the battery posts, check voltage at cable ends at battery, (they should be the same) check voltage at other ends of battery cables (should be very close to the same, dont remember the volt drops). The ground on any electrical system is the most important connection you can have. a poor ground will make a starter drag or not function at all. Any time you replace anything on an engine you should re-torque all bolts and connections within a few hundred miles or so.
check and re-check your grounds!
check and re-check your grounds!
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Freshman User
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Thanks for the help I will try to trace down the problem. But as far as it not charging good when I am driving around ? I can drive around all day and a few minutes after I turn it off you can tell the bett. are still slow.
Post Fiend
Joined: Nov 2003
Posts: 21,285
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From: Nutter Fort, WV
Start by getting the batteries load tested at an auto parts place, NAPA, Advance or Autozone.
Important, at least one battery negative cable must be removed from the post before and while you load test the batteries.
Important, at least one battery negative cable must be removed from the post before and while you load test the batteries.
Senior User
Joined: Oct 2005
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From: mooringsport louisiana
I agree , have the batteries checked .Diesels are a little hard on the batteries .Make sure all connections are nice and clean also . I changed my alt sunday , was only putting out around 12.5 volts . Would just barely keep up during the day . At night it would not keep up and it would run down the batteries . Sure am glad I have a lifetime replacement warranty...lol.
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Joined: Dec 2004
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Just had my alternator checked at Autozone, was putting out around 13 volts, but only 3.3 amps. I was having the same problems. I bought a new 100 amp alternator at Autozone for $77 plus tax with a lifetime warranty (duralast brand). My truck starts a lot easier now, my wipers move faster, and my headlights are brighter now. Autozone checked it without having to remove it from the truck.
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