Battery Drain..
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FTE Legend
Joined: Aug 2004
Posts: 37,887
Likes: 20
From: North Central Rural Sask.
Battery Drain..
Ok I posted a problem awhile go with my 89 f150 302 5 speed. I posted that the battery was going dead overnight. Today i finally got to check it (posted the poriginal thread like a year ago lol) by removing the negative battery post, taking a test light, and seeing what was going on.
I had the bright light. Ok so i started fiddling around and i tok the fuses out of my alarm system on it. Same thing, then I noticed the light for under the hood. I pulled that out, and when i tested, there was no light at all (not even a dim one, I dont have a radio in it right now either) I put it back in and played around some more and it seems like the light under the hood is causing the problem. I just took the light out for now.
Anyways does it sound right that the light could be sticking on, (I closed the hood and i couldnt see a light under the hood either) or is there something else on that circuit I should be checking.
I dont have a wiring schematic to tell what is all on the circuit either.. if someone has one handy!
I had the bright light. Ok so i started fiddling around and i tok the fuses out of my alarm system on it. Same thing, then I noticed the light for under the hood. I pulled that out, and when i tested, there was no light at all (not even a dim one, I dont have a radio in it right now either) I put it back in and played around some more and it seems like the light under the hood is causing the problem. I just took the light out for now.
Anyways does it sound right that the light could be sticking on, (I closed the hood and i couldnt see a light under the hood either) or is there something else on that circuit I should be checking.
I dont have a wiring schematic to tell what is all on the circuit either.. if someone has one handy!
Senior User
Joined: Feb 2007
Posts: 223
Likes: 0
From: Kaukauna, WI
I had the same problem once. Brand new battery and everything. After suffering for another 6 months of jumping it every morning or leaving the battery charger on all night long, I took the battery back to where I bought it and discovered the NEW battery was bad. They warrantied it. Another brand new battery and the problem went away.
Try another new battery, you may have a rare BAD new batt.
Try another new battery, you may have a rare BAD new batt.
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FTE Legend
Joined: Aug 2004
Posts: 37,887
Likes: 20
From: North Central Rural Sask.
I got my battery tested over and over, they wont take it back, cause its a good battery, and it is fairly new, and hardly used.
The problem for sure isnt the battery, and the alternator is charging just fine.
Heres the original thread, and, like i said, I had the battery tested, and its fine.
https://www.ford-trucks.com/forums/7...-runs-dry.html
The problem for sure isnt the battery, and the alternator is charging just fine.
Heres the original thread, and, like i said, I had the battery tested, and its fine.
https://www.ford-trucks.com/forums/7...-runs-dry.html
Senior User
Joined: Oct 2003
Posts: 130
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From: Southern California
Not sure this truck has them because of its age. Do your sunvisors have a lited mirror in them? If so check to make sure they are going off when the visors are up.
Have you tried testing the switch that controls the light under the hood?
Have you tried testing the switch that controls the light under the hood?
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FTE Legend
Joined: Aug 2004
Posts: 37,887
Likes: 20
From: North Central Rural Sask.
No mirror visor lights, I havent tested the switch, so far just took the bulb out, and it seems to have solved it, via the test light on the neg battery cable. I think that would stop the flow of power, even if the switch was bad. (I will one day test the switch but not having a light under the hood isnt a big deal right now)
Elder User
Joined: Aug 2007
Posts: 502
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Do you have a DVM?Check volts after the truck sets for about 10-15min.Then remove the neg side of the battery for the nite.Next day check volts before you hook up the neg side to the battery.Should read the same.If it starts then no problem with battery!Then rehook your dvm start pulling fuses.Also could be alternator problem.
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FTE Legend
Joined: Aug 2004
Posts: 37,887
Likes: 20
From: North Central Rural Sask.
Again, ive tested my battery a few times, its perfect.
I think from what I gather, testing with a dvm would be the same as using a light, no?
I think the alternator is charging, Ive done the old yank the battery cable off while the truck is running, and it stays running, test.
I think from what I gather, testing with a dvm would be the same as using a light, no?
I think the alternator is charging, Ive done the old yank the battery cable off while the truck is running, and it stays running, test.
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Elder User
Joined: Aug 2007
Posts: 502
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You really need a DVM to check volts. This test light could be on dim or bright.Doesnt tell correct volt reading. Normal battery reading 12.6-12.8.after start up 14.2-14.6.
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Thread Starter
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FTE Legend
Joined: Aug 2004
Posts: 37,887
Likes: 20
From: North Central Rural Sask.
Well I have a DVM and its no problem to check the "fuse removal type test" that way over the light, would give my DVM a little work out haha.
Guess I could double check the alternator the make sure its pumping out the proper power. Wouldnt hurt anything to double check.
Guess I could double check the alternator the make sure its pumping out the proper power. Wouldnt hurt anything to double check.
Cargo Master
Joined: Jun 2002
Posts: 2,033
Likes: 32
From: Aurora,Colorado
If the truck is sometimes parked on a side of a hill-the mercury switch that turns on the engine bay light can close and cause the light to go on and run the battery down.
I have had this happen on some of my previous vehicles.
Do you sometimes park the vehicle on a hill or slope overnight??
I have had this happen on some of my previous vehicles.
Do you sometimes park the vehicle on a hill or slope overnight??
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FTE Legend
Joined: Aug 2004
Posts: 37,887
Likes: 20
From: North Central Rural Sask.
No, i dont, where I live its pretty damn flat, and where I park, its a flat area.
We sometimes get bugged that if we let our dog ran away, you could still see him running 3 days later!
We sometimes get bugged that if we let our dog ran away, you could still see him running 3 days later!
Senior User
Joined: Aug 2007
Posts: 136
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Had similiar prob on an 88 F250 where it would sit over night with a perfectly well charged battery then in the morning, nothing, wouldn't start. Had everything checked, pulled all the fuses, but still had like 600mA draw on the battery. Finally replaced the voltage regulator. Turned out there was something amuck inside the silver box causing the battery to drain out. Think the way I found it was to have my ammeter in series with the battery then pulled the connectors from the volt regulator then the meter went from 600ma to close to zero, indicating something shorted in the regulator.
Senior User
Joined: Oct 2003
Posts: 480
Likes: 1
From: Elyria, Ohio
Don't pull battery cables while engine is running; you can damage the alternator by doing that. This method of testing survives from the day when cars had generators. Do a search on this subject to get more info.
