Battery Drained Overnight
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Battery Drained Overnight
Hi guys went out to the truck this morning to a dead battery. The battery's were very dead. so I hooked them up to a charger and went back out to start and found a warm alternator......My be where my problem is. Should there be voltage going to the alternator when the truck is off?
Thanks
Thanks
Hotshot
Joined: Jan 2011
Posts: 18,849
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From: Puget Sound
That depends. Unplug the connector on the alternator and check voltage on both small wires. Do you have 12V on both small wires? If yes, the ignition switch is highly suspect. If only one has 12V, the alternator may fall in line with the rest of us that have had recent alternator failures.
Thread Starter
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Senior User
Joined: Aug 2011
Posts: 301
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That depends. Unplug the connector on the alternator and check voltage on both small wires. Do you have 12V on both small wires? If yes, the ignition switch is highly suspect. If only one has 12V, the alternator may fall in line with the rest of us that have had recent alternator failures.
Hotshot
Joined: Jan 2011
Posts: 18,849
Likes: 179
From: Puget Sound
It doesn't look good for a warm alternator just sitting there. You can disconnect the big wire and hook the small connector back up. If you are familiar with how to measure current between that lifted big wire and the post it was connected to on the alternator, that would be the final test. Otherwise... you can take it someplace and have it tested.
Thread Starter
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Senior User
Joined: Aug 2011
Posts: 301
Likes: 1
It doesn't look good for a warm alternator just sitting there. You can disconnect the big wire and hook the small connector back up. If you are familiar with how to measure current between that lifted big wire and the post it was connected to on the alternator, that would be the final test. Otherwise... you can take it someplace and have it tested.
Thread Starter
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Senior User
Joined: Aug 2011
Posts: 301
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Ok well here I am again.......Had no problems till yesterday morning went to start the truck and they are back down to like 8V......What was the fix for the alternator draining? Replace it?
Senior User
Joined: Mar 2012
Posts: 492
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From: Jenkintown, PA
Yes, if the alternator is warm and the batteries are going dead the alternator probably has a shorted diode and it needs to be replaced.
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