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Hello! I'm trying to track down a nagging problem on a 2006 Town & Country, base model. Basically, the battery drains down after a couple days, often times ending up stone-dead. With the battery charged, everything appears to work exactly as it should, and the charging system is putting out a little over 14 volts. Driving it every other day or so keeps the problem at bay, but it also can sit for a week between uses. I started by replacing the battery (it was fairly old anyway) but when the issue continued, I started digging deeper.

Disconnected the battery and tested amperage draw. About an amp initially, after a few minutes dropped to 0.18 amps. 20 minutes later the reading was the same.

Crawled all over the van looking for stuck switches, lights staying on, loose door latches, etc. Found nothing wrong. Turned every switch possible to "off" but no change.

Pulled each fuse one at a time. Absolutely no change from any of them except the IOD fuse, which dropped the amp draw to zero. Unfortunately, this doesn't tell me which IOD-powered item is the culprit. I also pulled each relay just for grins, but no change.

Disconnected the alternator wiring, no change.

Hooked up a scan tool did a full DTC scan. The most interesting codes that came back were "10 Front Control Module Message Not Received" "51 Left Turn Signal Indicator Open" "52 Right Turn (ditto)" "56 IOD Wakeup Cluster Output Open". I attempted to clear these codes but they came right back.

Also just for grins, I went all over the van and cleaned all of the grounding points I could find. We seldom use salt here and rust is almost never an issue, but an old mechanic I once worked for made me do that on just about everything and now I can't leave them alone.

At this point, my research is pointing to (A) corroded fuse panel, (B) failed front control module, or (C) failed body control module. Any of these items are expensive enough that I'd prefer not to just "buy it and try it." I'm pushing the boundaries of my (admittedly limited) mechanical knowledge as it is, and am wondering if someone could give me some tips for the next steps? Am I completely missing a likely problem?

Thanks!!
 

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. . . Hooked up a scan tool did a full DTC scan. The most interesting codes that came back were "10 Front Control Module Message Not Received" "51 Left Turn Signal Indicator Open" "52 Right Turn (ditto)" "56 IOD Wakeup Cluster Output Open". I attempted to clear these codes but they came right back. . . .
You observed a 0.18 amp or 180 milliamp parasitic draw. This is excessively high and with the vehicle shut down and all modules experiencing time out, it should be in the range of 10 - 30 milliamps. So there is one or more electronic modules which are not going to sleep / powering down.

One of the codes presented is giving you a hint to the source of the problem. "56 IOD Wakeup Cluster Output Open"

I believe the instrument cluster is NOT going to sleep as the wakeup circuit to the cluster is shorted to ground / power or has an open circuit. Check the wakeup sense circuit between the BCM and instrument cluster. See attached image.

You can disconnect the instrument panel electrical connector. Does the electrical draw drop to a range of 10 - 30 milliamps? If YES then you have narrowed the problem to the instrument cluster and / or wiring cable to the cluster or an issue with the specific BCM circuit between the two.

Instrument Cluster to BCM.gif
 

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Troubleshooting tests from the Body Diagnostic Procedures book,
 

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Discussion Starter #4
Thank you both for your helpful information! Using the diagrams from Allan, I went step-by-step through Imperial's diagnosis guide. Everything checked out until Step 4. Basically, the wiring tests good up to the instruments and the BCM is not producing a strange voltage on the wakeup circuit. According to the instructions, the next step is to replace the instrument cluster. Unfortunately, with the instrument cluster disconnected and lying in the back seat, the draw is still present- about 0.22 amps. It's significantly warmer today which may account for the different reading from yesterday. The reading doesn't change when I plug it back in either. Could the computer be looking for a signal from the cluster telling it to turn something else off?
 

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Since the draw is on some IOD-powered circuit, you may want to begin unplugging components on that circuit. Begin at the BCM connectors? Some draw is normal for memories,etc. but 220 mA is excessive.
 
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. . . Could the computer be looking for a signal from the cluster telling it to turn something else off? . . .
The BCM would signal and control the wake up function of the instrument cluster; not the other way.

. . . Since the draw is on some IOD-powered circuit, you may want to begin unplugging components on that circuit. Begin at the BCM connectors? Some draw is normal for memories,etc. but 220 mA is excessive. . . .
Attached is a consolidated image of the modules that draw power through IOD fuse #14. Unfortunately this is based on 2005 minivan electrical schematics. Model year 2006 introduced the TIPM / totally integrated power module and this may have resulted in some wiring changes. You can use this as a guide and disconnect modules as ImperialCrown suggested.

Fuse 14.gif
 

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I believe that the 2001-2007 RS minivan was still an IPM/PDC fuse/relay module.
The 2008+ RT minivan went to TIPM power distribution management.
 
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Discussion Starter #8
I believe we have success! I started brute-force testing off of that fuse diagram by unplugging one component after another. Unplugging the radio dropped the current draw to 20mA; this seems strange to me because the radio has been behaving perfectly. I'm not going to argue with it, however! We can live without a radio for a while if the van starts when we need it. It was very helpful having a clear list of items coming off of that IOD fuse.

Thank you both again for the detailed information!
 

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. . . Unplugging the radio dropped the current draw to 20mA; this seems strange to me because the radio has been behaving perfectly. I'm not going to argue with it, however! . . . . .
Glad that you were able to isolate the source of the excessive, parasitic electrical drain.

Does your vehicle have steering wheel controls for radio volume control and mode control? They are mounted on the backside of the steering wheel spokes. If present the switches are typically rocker type. When not activated they reside in a neutral or center position. To control the radio you push on one side or the other of the rocker, it depresses and sends a unique analog voltage signal to the instrument cluster. The cluster interprets and then sends a digital message over a vehicle chassis network to the radio to affect an action. So the radio is connected to a chassis network.

If one of those switches sticks in an active position, there will be constant messages sent over the chassis network to the radio even with the ignition key switch in the OFF position and engine not running. This creates a small milliamp drain on the electrical system because the network is active.

Check the switches for sticking. Maybe someone had "sticky fingers literally" and some substance got transferred to the switch and is impeding its free movement.
 

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Discussion Starter #10
Nope, no wheel control buttons in this one. Could a similar issue be present in the radio buttons themselves? They all appear clean and feel correct, but that doesn't guarantee that nothing got behind them.
 

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. . . . Nope, no wheel control buttons in this one. Could a similar issue be present in the radio buttons themselves? They all appear clean and feel correct, but that doesn't guarantee that nothing got behind them. . . . .
When you monitor parasitic draw try depressing and holding radio buttons in that state. Does the parasitic draw change? That might give a clue if a stuck radio button is the culprit.
 
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