Bad battery drain
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Cross-Country
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Bad battery drain
Hello people,
My F350 has a really bad battery drain, i measured the parasitic draw on each positive wire, all are acceptable except for one, and that one is bad
It is the engine harness that connects to the passenger side battery, and BAD means a draw of 0.6 amps, which is considerably more than what is good
I know what you are saying, it's the alternator. But why, why could it be so easy/
And yes it's become really interesting, the alternator has a 0.1 amp draw, which is not ideal but ok. Where's the 0.5 amp draw?
Yes, i need help
I disconnected the alt. and the draw was still there, but 0.1 amps less, 0.5 amps
I also disconnected the GPCM and the IDM, then from the PCM, no change whatsoever. I tried to do both connectors below the P.S. reservoir but it was quite tough and realized that it wouldn't have been worth
I thought that it is connected to other things but after a quick review of the wiring diagrams it didn't appear to, not even the control units previously mentioned
Is it actually connected to something else? Any ideas on what could cause this?
My F350 has a really bad battery drain, i measured the parasitic draw on each positive wire, all are acceptable except for one, and that one is bad
It is the engine harness that connects to the passenger side battery, and BAD means a draw of 0.6 amps, which is considerably more than what is good
I know what you are saying, it's the alternator. But why, why could it be so easy/
And yes it's become really interesting, the alternator has a 0.1 amp draw, which is not ideal but ok. Where's the 0.5 amp draw?
Yes, i need help
I disconnected the alt. and the draw was still there, but 0.1 amps less, 0.5 amps
I also disconnected the GPCM and the IDM, then from the PCM, no change whatsoever. I tried to do both connectors below the P.S. reservoir but it was quite tough and realized that it wouldn't have been worth
I thought that it is connected to other things but after a quick review of the wiring diagrams it didn't appear to, not even the control units previously mentioned
Is it actually connected to something else? Any ideas on what could cause this?
Thread Starter
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Cross-Country
Joined: Feb 2022
Posts: 84
Likes: 16
It's not the other crap, it is in the engine circuit, no fuses
Fleet Owner
Joined: Nov 2003
Posts: 27,890
Likes: 3,610
The v-reference circuits (critical engine sensors) are powered out of the PCM. The PCM fuse is F2.22. That is ONE of the critical engine circuits. This fuse also services critical 12V actuators. I would at LEAST try to see what happened with that one disconnected.
Fleet Owner
Joined: Nov 2003
Posts: 27,890
Likes: 3,610
Hello people,
My F350 has a really bad battery drain, i measured the parasitic draw on each positive wire, all are acceptable except for one, and that one is bad
It is the engine harness that connects to the passenger side battery, and BAD means a draw of 0.6 amps, which is considerably more than what is good
I know what you are saying, it's the alternator. But why, why could it be so easy/
And yes it's become really interesting, the alternator has a 0.1 amp draw, which is not ideal but ok. Where's the 0.5 amp draw?
Yes, i need help
I disconnected the alt. and the draw was still there, but 0.1 amps less, 0.5 amps
I also disconnected the GPCM and the IDM, then from the PCM, no change whatsoever. I tried to do both connectors below the P.S. reservoir but it was quite tough and realized that it wouldn't have been worth
I thought that it is connected to other things but after a quick review of the wiring diagrams it didn't appear to, not even the control units previously mentioned
Is it actually connected to something else? Any ideas on what could cause this?
My F350 has a really bad battery drain, i measured the parasitic draw on each positive wire, all are acceptable except for one, and that one is bad
It is the engine harness that connects to the passenger side battery, and BAD means a draw of 0.6 amps, which is considerably more than what is good
I know what you are saying, it's the alternator. But why, why could it be so easy/
And yes it's become really interesting, the alternator has a 0.1 amp draw, which is not ideal but ok. Where's the 0.5 amp draw?
Yes, i need help
I disconnected the alt. and the draw was still there, but 0.1 amps less, 0.5 amps
I also disconnected the GPCM and the IDM, then from the PCM, no change whatsoever. I tried to do both connectors below the P.S. reservoir but it was quite tough and realized that it wouldn't have been worth
I thought that it is connected to other things but after a quick review of the wiring diagrams it didn't appear to, not even the control units previously mentioned
Is it actually connected to something else? Any ideas on what could cause this?
Thread Starter
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Cross-Country
Joined: Feb 2022
Posts: 84
Likes: 16
I have been offline for a long time
The drain is through the alternator exciter wire, when I unplug the alternator connector and it has normal draw, but when it is plugged again, it is very high
What alternator brand should I get?
The drain is through the alternator exciter wire, when I unplug the alternator connector and it has normal draw, but when it is plugged again, it is very high
What alternator brand should I get?
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Hotshot
Joined: Dec 2014
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From: Jersey Shore
So your saying the I circuit always has 12v? If that’s so, it’s not an alternator issue. The I circuit should be at 0v when the key is off.
If there is 0v on I when the key is off, then you do have an issue with the alternator regulator, it’s feeding the sense A circuit into the I circuit.
If there is 0v on I when the key is off, then you do have an issue with the alternator regulator, it’s feeding the sense A circuit into the I circuit.
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Cross-Country
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So your saying the I circuit always has 12v? If that’s so, it’s not an alternator issue. The I circuit should be at 0v when the key is off.
If there is 0v on I when the key is off, then you do have an issue with the alternator regulator, it’s feeding the sense A circuit into the I circuit.
If there is 0v on I when the key is off, then you do have an issue with the alternator regulator, it’s feeding the sense A circuit into the I circuit.
What could be the issue if that's the case?
My truck may be back on Friday
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