IPDM fuses always have power?

Photonfanatic

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Hi all. I have a bit of a noobish electrical question. I don't really want the make and model of the car to become the prime focus here, as I've already been over to the forums for that car and nobody seems to really have much of an answer. Its a 2003 Nissan Altima. So it has CAN and an IPDM.

So I have this car, and it keeps running the battery down overnight. For a long time I thought it was the "parking lights" function, which some call the "driving lights" or daytime running lights". Its the tail lights, and the orange lights in the headlights. For some strange reason, they stay on for a whopping 10 minutes before they go off. After some research, I found that an OE Scanner can be hooked up to the Body Control Module, and the time for how long these lights stay on, can be set. This may be somehow related to the problem, but who knows. Anyway, I was reading an article on how to diagnose battery drains, and it said to check the fuses when the key is out of the ignition. It said that if a fuse has power when the car is off, then that system is likely the cause of your power drain. And of course from there, you can likely find out why the system is drawing power when its not supposed to be.

Not sure that idea makes a whole lot of sense to me, as the radio memory, and the engine computer like to have constant power. So there's 2 fuses right there, that I would think would always have power. Well I found 4 total fuses on the car that always have power. And I really don't know know what they go to, as they don't seem to be labeled anywhere. Thanks Nissan, for not labeling your IPDM fuses.

The only thing I can come up with right now, is that it could be the battery itself. I bought a reduced price battery from a junkyard, in a effort to save money. The guy said that the batteries they sell are "new", but have sat on the shelf for 6 months at some store somewhere. He said that the battery manufacturers only let them sit on the shelf for 6 months, then they sell them as discounted items to places like the junkyard I bought it from. They peel all the stickers off. The battery also comes with a 6 month warranty. So I can return it if need be. But it still charges up, and will still run the car just fine. It doesn't seem to be weak, and the voltage gauge, nor the battery light, comes on in the car. But I've heard of batteries causing some strange problems. Anyway, that's all I've got, look forward to reading the replies.
 

ttocs

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there are plenty of fuses that still have power on them. Its certainly not a good way to check. The way that is recomended is to hook up an amp meter which requires you disconnect the battery and put the meter in between the two contacts(battery and wire) and then take an amp reading. Now from there you go to your fuse box and start pulling one fuse at a time. Eventually you will pull the fuse that relates to teh current draw and from there you can normally narrow down the 3-4 things that might be on it.
 
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Photonfanatic

Photonfanatic

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But if you disconnect the battery, how would you get a power reading? Not sure I follow you there. What if you took the fuse out, and left the battery hooked up. Then you plug your prongs on the amp meter, into each side of the fuse's little terminals in the fuse box. Where the fuse itself would have plugged in. Then, your amp meter will of course read the current that the fuse would be getting.

Now, you make note of that number. Lets say for example, a certain fuse is drawing 2.3 amps. But then you look up the factory specs, and its only supposed to be drawing 0.8 amps. At that point you'd know that system was somehow drawing way more power than it was supposed to.

Is this what you mean? Sorry I'm a pretty big noob to electrical type stuff.

And to clarify, you're talking about something like this, correct?

http://www.kmart.com/electronic-spe...p-00918974000P?prdNo=2&blockNo=2&blockType=G2
 

CC'S95GT

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You disconnect the battery then connect the meter between the cable and the battery post. So ALL electrical pwr runs through the meter. Set meter on AMPS.
The meter will show all battery usage. Then start pulling fuses till the meter reading stops or slows significantly.
The link is a fuse tester. You need a digital multimeter.http://www.summitracing.com/parts/shc-3482141/overview/
 

ttocs

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on a volt meter you measure by putting the meter in parallel. Meaning you can just slap the +/- on top of the terminals and it will make a reading. For amperage you need to read the current and that has to be put in series with the circuit so when you disconnect the battery you put the meter on the disconnected battery terminal and the disconnected battery connector so as he said above all the current will go through the meter. Them make amp meters with a clamp you just slap over the power wires but I don't think they are good for the low readings we are doing. Pulling the fuse and inserting the meter will tell you if a fuse circuit is drawing power but you will not know if its drawing more then others or if its the bad circuit.
 
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Photonfanatic

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Ok I got the idea thanks for the help! Much appreciated.

Now I got to get a multimeter that works lol. Mine was $12 at walmart, and when you switch the probe over to the amp setting, it reads 0.00. The car should have some amp draw. According to what I've learned so far, it needs to be under 50 milliamps. Plus its really hard to plug the probe into the 10a spot, so there is likely some kind of a problem with the multimeter. I'll see about getting that craftsman off summit
 

ttocs

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Depending on your meter its not uncommon that you need to switch the red/pos lead on the meter to a different spot on the meter because of the difference in how its measured. My meter for example has 3 holes for the test leads. The black is common and never moves but I need to swap the red lead from the usual red spot labeled V(voltage) to the other red terminal labeled A(amperage) or sometimes "I" (current).
 
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Photonfanatic

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Well it turns out that meter was broken but I get a new one. And what its telling me is a little confusing. Either the meter is confused, or I'm reading it wrong. As you can see in pic 1, I have a parasitic amp draw of .252 amps. Also known as, 252 milliamps. But if you look at the second pic, I changed the setting to milliamps. Now somehow its saying that I've only got a parasitic draw of 2.52 milliamps. It would seem that the meter is confused about where to place the decimal point. Typically you're not supposed to have a parasitic draw over 50 milliamps. So clearly 252 milliamps, is about 200 too many. So that could be killing the battery overnight.

But on the other setting, the milliamps setting, the meter is saying that its WAY below 50 milliamps, and the draw is in fact only 2.52 milliamps. So which is it? Am I doing it wrong?







 

ttocs

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what is that larger clip that is on the top of the battery? A battery charger? If so disconnect it and try reading it again. Honestly the numbers are not all that important other then you need to make them go down. I normally just hook it up and start pluckin fuses. You will know when you find the right one and THEN the fun begins...
 
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Photonfanatic

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Yeah I found one already, it had a whopping 2 amp draw. Know what it was? It was labeled "spare" on the fuse diagram. It was even the correct rating, a 10a fuse. Spare? Spare what? lol. Everything still works, so yeah. Go figure. Freakin' Nissan...

Now I've still got a 252 milliamp draw to find, but I'm sure yanking the fuses will reveal it.

Yes that is a battery charger clip, but the reading is the same wether its on or off. So I just went ahead and used it, so I'd have something to attach my meter lead to. Can't just hook up the terminal and use that, cause the car runs it down.
 

ttocs

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def take the charger off as it could mess with the fact it needs to be in series with the batter/car and now with that across the +- its a series parallel circuit. 2 amps is huge its hooked up to something..... You will never get it down to 0 but 252mA is still pretty high.
 
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Photonfanatic

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Here is what's drawing 2 amps and killing the battery. "Spare" lol. Thanks, nissan. Anybody got any idea where I might find out what system that fuse really goes to? Something other than "spare". Need some idea of where I might start looking for the problem.

 

ttocs

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is it possible the spare fuse is missing and your really looking at the 3rd one down that's the eng control?
 
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Photonfanatic

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No I found out that this "spare" fuse is the fuse for the TCM. The transmission control module is on that fuse from the factory. Explains why I lose the gear selector light when the fuse is pulled, I guess being a transmission fuse its related. Leave it to nissan to label it "spare". But hey why not. They labeled 2 fuses in the interior fuse panel as "electronic parts".

Anyway, not real sure how to start diagnosing this, as I'm still something of an electrical noob. Where would you guys start? By looking at the TCM itself, perhaps pulling it off the car and having it tested?
 

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The only thing you can do is pull the loads off that circuit. If the TCM is like a ECU type component you'll have to replace it, if that's your draw. If you unplug the TCM and the draw is still there, look elsewhere. You're on the right track.
 

ttocs

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not you need to figure out what is all powered on that fuse. Not sure where to tell you to look short of a haynes manual or something....
 
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Photonfanatic

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Well I found the entire shop manual from nissan online. I'll start sifting through that. Its not very user friendly. I'll report back any new developments.
 

ttocs

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its looks bigger then it is. It might be as thick as phone book but you only use a few areas. First check is that fusebox. MAke sure its dead there or what if it does have power pull the fues and see what dies.
 

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