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Battery Drain

JOHNFAK
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Mopar1973Man

Mopar1973Man

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No. The Alternator fuse is hooked at the head of the main bus going into the PDC so it has the illusion of the alternator and PDC both.

 

The black lead on the alternator should be dead without a fuse in place.

 

The red lead terminal is the battery supply and also powers the PDC main bus. So now the loads as shown above break off in separate fuses. Then break off again to the Cab fuse panel too.

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MnTom

MnTom

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John, maybe I misunderstood what you meant. I thought you said that if you pulled all the wires from the 140A fuse and still had a draw at the fuse, but now I am re-thinking that. I agree with Mike. Pull fuses and check each spot for the draw.

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CSM

CSM

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Then what is bypassing the fuse block but is powered by the battery?  What is wired onto the positive stud? I know you don't have any programmers with the P pump, but you have an electric fuel pump? You've eliminated everything you pulled the fuse for, so the list should be getting shorter.  

 

Unfortunately, you don't know for sure what all the wiring is on your new truck... so it could be several things from Gauge power to a relay for the fuel system.  It should be easily enough tracked down though. Just keep following the amperage draw with your multimeter in the same way as the fuses.  Test by unplugging if that is easy, or by checking for a draw with your meter. 

Edited by CSM
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JOHNFAK

JOHNFAK

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You can see what I'm doing here.

alt_fuse.jpeg

All accessories are tied to red battery cable which is not connected to battery.

When I probe from battery to the 140a studs with ALL alternator and FSS wires removed ( so only studs showing i remove those 4 wires in pic) I still get 0.5a draw.

Removing fuses made no difference. Both in PDC and in cab.

Edited by JOHNFAK
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CSM

CSM

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Huh.  So the probe is going from the positive bat terminal to the 140A stud... and you are reading 0.5A.   

 

 

I am 99% sure that the positive lead that you have disconnected powers the 140A stud.  You can check... (also check if the disconnected lead has 12-14v on it from the pass side... I don't think it does, but it might skew your results if it is connected to that battery.)  

 

So, if the 140A stud is powered through the disconnected lead in the picture, you still can have a leak from the wires connected to the lead.  

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JOHNFAK

JOHNFAK

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Huh.  So the probe is going from the positive bat terminal to the 140A stud... and you are reading 0.5A.   

 

 

I am 99% sure that the positive lead that you have disconnected powers the 140A stud.  You can check... (also check if the disconnected lead has 12-14v on it from the pass side... I don't think it does, but it might skew your results if it is connected to that battery.)  

 

So, if the 140A stud is powered through the disconnected lead in the picture, you still can have a leak from the wires connected to the lead.  

 

Yup - but I disconnect that red lead (connecting the 140a to the battery). So its two bare studs ........ and I probe from battery (+ve direct to the stud) and still read 0.5A

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CSM

CSM

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And you couldn't isolate it by pulling fues on the block there?  Weird.  well... it has to be there somewhere. You could try just probing from teh battery to the top of each fuse.  There is a small gap there a sharp probe should touch metal, so you shouldn't have to pull any.  You could even check the bags. 

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MnTom

MnTom

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Where does the black wire (looks like maybe two black wires) go? Have you pulled the nut on the fuse and checked just that wire? If you  pulled all the fuses the small black wire has been in the circuit for every test (doesn't look like any wrench marks on the nut)>

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JOHNFAK

JOHNFAK

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Where does the black wire (looks like maybe two black wires) go? Have you pulled the nut on the fuse and checked just that wire? If you  pulled all the fuses the small black wire has been in the circuit for every test (doesn't look like any wrench marks on the nut)>

Tom

Do you mean the black wire on the 140A ? I remove all 4 of those wires so there are only studs.

 

1) Remove and pin back the +ve cable from the drivers battery. Remove the cables from the passenger also.

2) Remove all four wires from the 140A circuit so only two studs are left.

3) On A~ mode on mulitmeter ...... bridge from +ve terminal to the stud on 140A. Reads 0.5A.

4) Start pulling fuses in PDC and CAB as well as relays. No change.

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Mopar1973Man

Mopar1973Man

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You need to have power to measure draw. So the red lead must stay from the battery.

 

Now you could pull each lead and measure from the RED cable stud to the lead to measure draw of each wire.

 

With power still hooked up you can pull one fuse at a time and measure across the fuse terminals of the panel and see the draw level of each circuit. When you find the heavy draw circuit tell me the fuse and I'll pull up the wiring diagram for it.

 

Right now you need to work your way down the power distribution system and find out which circuit is the heavy draw. 

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MnTom

MnTom

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Tom

Do you mean the black wire on the 140A ? I remove all 4 of those wires so there are only studs.

 

1) Remove and pin back the +ve cable from the drivers battery. Remove the cables from the passenger also.

2) Remove all four wires from the 140A circuit so only two studs are left.

3) On A~ mode on mulitmeter ...... bridge from +ve terminal to the stud on 140A. Reads 0.5A.

4) Start pulling fuses in PDC and CAB as well as relays. No change.

That is what has me confuzzled.You are saying the 140A fuse WITH NO WIRES ON IT still has the 1/2 amp draw.

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Wild and Free

Wild and Free

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Dumb question but have you isolated the batteries as in completely unhook everything from both and see if you don't have a bad cell draining the battery itself or just pull them and have them tested. I have not read through this entire thread very good but seems to be a lot of jumping around without starting at the source.

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