Battery drain
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Battery drain
I recently bought a 2002 expedition and about a week ago the battery light came on so I took it in and the alternator tested good and the battery needed to be replaced so I did. The light stayed on for about 60 miles after replacing the battery. A few days later it came back on and went off again and now it's on again. I tested between the negative battery post and battery wire and it has a draw of .24 amps so that's what 240 milliamp? Is that too much draw? What should I check next? Is there something that is a common battery draw? Also about a week after I bought the truck the doors started unlocking by itself over night. Are these related or separate? The battery light is driving me crazy any help would be great.
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It's most likely the alternator brushes are worn. If the battery isn't being kept fully charged because of the worn brushes, then the low battery can cause the unlocking issue.
If you're handy you can take the alternator off and replace the brushes set yourself, if not you'll have to replace the whole alternator. Oh and as far as it testing good, it will test good with worn brushes but will still fail in the vehicle due to a heavier electrical load.
If you're handy you can take the alternator off and replace the brushes set yourself, if not you'll have to replace the whole alternator. Oh and as far as it testing good, it will test good with worn brushes but will still fail in the vehicle due to a heavier electrical load.
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It's most likely the alternator brushes are worn. If the battery isn't being kept fully charged because of the worn brushes, then the low battery can cause the unlocking issue.
If you're handy you can take the alternator off and replace the brushes set yourself, if not you'll have to replace the whole alternator. Oh and as far as it testing good, it will test good with worn brushes but will still fail in the vehicle due to a heavier electrical load.
If you're handy you can take the alternator off and replace the brushes set yourself, if not you'll have to replace the whole alternator. Oh and as far as it testing good, it will test good with worn brushes but will still fail in the vehicle due to a heavier electrical load.
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That's a bad idea, it can cause voltage spikes and damage electronics. Also worth checking the rear wiper motor, if it is having trouble recognizing its home position it will keep drawing power and draining the battery. You can pull the fuse and see if it stops draining.
Fleet Owner
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I had the alternator tested and it was fine, the problem is after it sits for a day the battery light comes on and after driving it to work it will be off by the time I get there so I think the alternator is charging the battery as I drive, like it should, but when it sits something is draining it. And my battery/alternator gauge is steady when I drive.
Like I said earlier about the test, you're getting a false positive.
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The battery light will come on for more than just your alternator not working, it will come on when your battery is below a certain charge also which could be because of the alternator not charging or a parasitic drain on the battery or a number of other reasons. That being said I think I figured out the problem, I took out the under hood light when I tested my battery with my multimeter and didn't put the build back in and now the battery has stayed off. So I think the under good light either has a short or was staying on and draining the battery.
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Be aware that the alternator can fail without turning the light on. If the alternator is only putting out, say 10 volts, the light will go off but the battery will eventually run down to the point it won't continue to run the engine or start it.
Now the "needle" on the battery gauge is another thing. It shows the battery's "voltage". It is not a very sensitive gauge and is hard to tell just how much voltage is in the system.
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I put a few diodes in mine for a remote starter install so mine now reads voltage very nicely.
http://www.cleanvideosearch.com/medi...Id=82ll_34MVN4
Here's a vid I made.
http://www.cleanvideosearch.com/medi...Id=82ll_34MVN4
Here's a vid I made.
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