Battery drains overnight
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Cargo Master
Joined: Dec 2007
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From: Minnesota
Battery drains overnight
Yesterday morning I go to take my boys to school, X is completely dead, just a click from starter. Had old battery, so I got a new one, put it in and rig ran fine the rest of the day. Go out this morning, same deal. Got battery charged and truck running, can smell slight burning smell, kinda like plastic burning. Checked belt and any hoses and wires I could seeand or feel. Nothing seems out of place. Anyone had this issue before?
O yea, its an 02 X Limited 4X4 V-10.
O yea, its an 02 X Limited 4X4 V-10.
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Cargo Master
Joined: Dec 2007
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From: Minnesota
I'll give that a shot, but the alternator is only about 18 months old and I wouldn't think a bad alternator would drain a battery overnight, especially a new battery, or am I mistaken?
Senior User
Joined: Dec 2005
Posts: 348
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From: Hemet, California
If you drove it the day before it would be running off the battery if the alt is bad instead of running off the alt. Fire it up and drive with the headlights on, that'll tell you really quick. Just make sure your either letting it run at home or just around the block so if that is the case your not screwed
Tuned
Joined: Mar 2006
Posts: 455
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From: Luxemburg WI
I have had an alternator short out and drain the bat before. Could be a burned wire (smell) between the alt and bat too. Alt test could show it charges but could not be getting to the bat. Start the truck and remove the bat cable. If you can run lights ect with the bat unhooked, the alt is good.
I had an 88 Bronco that would drain the bat. Turned out to be a bad relay for the fuel pump. What gave it away was the pump would not prime the system when the key was turned on. The relay had stuck closed and the system would stay primed. I gave the relay a tap and the fuel pump ran for a second without the key on.
You could do a load test and start pulling fuses to find the draw if it goes that far.
I had an 88 Bronco that would drain the bat. Turned out to be a bad relay for the fuel pump. What gave it away was the pump would not prime the system when the key was turned on. The relay had stuck closed and the system would stay primed. I gave the relay a tap and the fuel pump ran for a second without the key on.
You could do a load test and start pulling fuses to find the draw if it goes that far.
Last edited by dzldenny; Mar 31, 2010 at 04:06 PM. Reason: Had another thought.
Posting Guru
Joined: Apr 2003
Posts: 1,089
Likes: 1
From: Michigan
I have had an alternator short out and drain the bat before. Could be a burned wire (smell) between the alt and bat too. Alt test could show it charges but could not be getting to the bat. Start the truck and remove the bat cable. If you can run lights ect with the bat unhooked, the alt is good.
I had an 88 Bronco that would drain the bat. Turned out to be a bad relay for the fuel pump. What gave it away was the pump would not prime the system when the key was turned on. The relay had stuck closed and the system would stay primed. I gave the relay a tap and the fuel pump ran for a second without the key on.
You could do a load test and start pulling fuses to find the draw if it goes that far.
I had an 88 Bronco that would drain the bat. Turned out to be a bad relay for the fuel pump. What gave it away was the pump would not prime the system when the key was turned on. The relay had stuck closed and the system would stay primed. I gave the relay a tap and the fuel pump ran for a second without the key on.
You could do a load test and start pulling fuses to find the draw if it goes that far.
Have your alternator checked first. Then make sure the battery is fully charged and find someone with an inductive ammeter. Hook it around the positive battery cable and you should see no more that 2-5 amps max with everything off. If it is more than that then you have some kind of parasitic load. Something is staying powered up after you shut the vehicle off and remove the key. Do you have any aftermarket accessories? Alarm, remote start, radio? These thinks are notorious for causing this problem. Start pulling fuses until the ammeter reads normal. You can identify the circuit that the load is on by doing this.
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Tuned
Joined: Mar 2006
Posts: 455
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From: Luxemburg WI
I've seen the alt and starter rebuild shop remove the bat cable on a 02 with the 5.4 with it running to test (it was good). Also, that's how the dealer showed me mine was working on my 88 Bronco with the 5.8 and Cali emissions. (BTW They were unable to find the shorted relay until they ruled out the alt) I've done it to countless EFI vehicles and never had a fried anything from it. I get your hesitance, all those electric majical wonders cost $$$$.
OK... I'm out. Don't want to start a
Good luck.
OK... I'm out. Don't want to start a
Good luck.
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Joined: Nov 2008
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From: Semper Fi tell I die!
I've seen the alt and starter rebuild shop remove the bat cable on a 02 with the 5.4 with it running to test (it was good). Also, that's how the dealer showed me mine was working on my 88 Bronco with the 5.8 and Cali emissions. (BTW They were unable to find the shorted relay until they ruled out the alt) I've done it to countless EFI vehicles and never had a fried anything from it. I get your hesitance, all those electric majical wonders cost $$$$.
OK... I'm out. Don't want to start aGood luck.
OK... I'm out. Don't want to start a
Good luck.
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