Why does the battery drain down?

Tiny
RPORTER842
  • MEMBER
  • 2006 DODGE RAM
  • 2WD
  • AUTOMATIC
The batteries on my 2006 Dodge Ram Diesel run down after a couple of days. I checked the amp draw on the fuses and found that the fuse labeled IOD-CNN/Radio/Under Hood Lamp/WCM/SDARS/HFM was fluxuating between 1 amp and 2.5 amps with ignition off, doors closed and hood lamp removed. What do the abreviations for this fuse mean and is the fluxuation normal?
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Wednesday, August 24th, 2011 AT 2:20 AM

58 Replies

Tiny
HMAC300
  • MECHANIC
  • 48,606 POSTS
It does that because it keeps the memory in your radio alive and clock running so you don't have to reset it everytime you turn the key on. This guide can help

https://www.2carpros.com/articles/car-battery-dead-overnight

Please run down this guide and report back.
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Wednesday, August 24th, 2011 AT 3:22 PM
Tiny
RPORTER842
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The guide showed me it was the fuel pump relay stuck on, thank you.
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Friday, August 26th, 2011 AT 3:21 AM
Tiny
GOLDNUGGET
  • MEMBER
  • 5 POSTS
  • 2005 DODGE RAM
  • 5.7L
  • V8
  • 4WD
  • AUTOMATIC
  • 300,000 MILES
I have rebuilt two alternators and bought a new one. All three have the same problem(Denso 160 amp presently in the PU, Bosch 130 amp and TYC 130 amp). I think I have ruled out the alternator as the problem. The situation is at start up the alternator reads 14.45v. As I drive the PU throughout the day the voltage starts dropping slowly 14.4, 14.3 14.2.13.9v. Steady voltage is wanted. 14.7 to 13.7v about the limit range. I am going to list what has been tested.
- Battery keeps the charge after couple of hours sitting with everything off on the PU is 12.67v. PU starts with no problem. A night of sitting the battery was reading 12.4v in the morning. After testing parasitic mA drain, found out about fuse 51 drawing 1000 mA! I pull the fuse to stop the drain. This a factory set up to keep radio, in cabs lights and bells and whistles ready. Poor design. I thought this would help my situation to no avail. This why the 12.4v read on the battery.
- At idle, Alternator +B post and positive battery post read the same 14.12v.
- At idle, negative side to alternator frame(gnd) 14.12v. Same as the +B read.
- Cleaned all (3) ground connections which lead from the negative battery terminal.
- Checked all negative and positive wires from alternator to battery.
- Engine at 1500 rpm and everything turned on lights, AC, mirror heaters, radio etc. Measured the positive side of the alternator at 95 mV and negative side 106 mV.
- Checking for parasitic drain (mA), isolated the 1.0 amp drain the PU had about 20 mA drain read.
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Wednesday, June 23rd, 2021 AT 6:58 PM (Merged)
Tiny
SCGRANTURISMO
  • MECHANIC
  • 4,897 POSTS
Hello,

Okay, so the fuse that had a 1 amp parasitic draw on it is not the problem. The problem, is however, on the circuit, or one of the circuits, that that fuse is protecting. Can you tell us which fuse you got the reading from, and we can provide you with the wiring diagrams of the circuit(s) that the fuse is protecting so you can track down the parasitic draw problem.

Thanks,
Alex
2CarPros
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Wednesday, June 23rd, 2021 AT 6:58 PM (Merged)
Tiny
STEVE W.
  • MECHANIC
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As Alex said you need to look at the circuit that fuse 51 powers. However as for the voltage drop from the alternator, that is normal. At initial start up the alternator puts out a higher amperage and voltage to bring the battery back to full charge. Then it will slowly taper the voltage down as the battery reaches full charge. 20mv is a normal drain for the ECU and clock. As for the high drain item, I would start by unplugging the modules one at a time, the hands free modules are a known failure item as are the radios.
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Wednesday, June 23rd, 2021 AT 6:58 PM (Merged)
Tiny
GOLDNUGGET
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  • 5 POSTS
So far I have removed the underhood lamp to be cleaned. Bulb is gone. Need to replace. Now for the other modules I have not pulled the connections. Where exactly is the Free Hands Module to be found behind the front dash panel of the PU? As the schematic shows " behind left side of dash"? What does the Free Hands module look like so be easier to find?
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Wednesday, June 23rd, 2021 AT 6:58 PM (Merged)
Tiny
DOCFIXIT
  • MECHANIC
  • 18,828 POSTS
As Steve said voltage from alt will go down after start up as battery is charged to capacity then alt reduces. As long as charging voltage stays 1.5v higher than full battery voltage all is good. The 12.4v after sitting overnight leads to suspect battery. Have a load testdone on battery
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Wednesday, June 23rd, 2021 AT 6:58 PM (Merged)
Tiny
GOLDNUGGET
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  • 5 POSTS
Understand this correctly. Battery is fully charged at 12.7 v plus higher voltage 1.5 v = 14.2 v. So, if charging is at 13.9 v then I have a problem? I have had this voltage reading this week on the Dodge ram. Most of the time the alternator is between 14.0 - 14.1 v. Will this work at these levels? Also, with the 12.4 battery reading in the morning, the PU has a 1000 mA drain from fuse 51. Was asked to unplugged the Free Hands Module first in that circuit to find which module has the amperage drop. Under the dash, knowing where to look and what it looks like would be a great help. I am guessing, is behind the radio or same area?
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Wednesday, June 23rd, 2021 AT 6:58 PM (Merged)
Tiny
HERB DUNCKER
  • MEMBER
  • 1 POST
  • 2004 DODGE RAM
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 92,000 MILES
I have dodge diesel 3500. Battery dies after 3 days of sitting. Replaced w/2new battery's no improvement. When I first crank up the truck amp gauge showing a load about a 13volts after couple mins, of runing. Alternator goes to no load at 14+ volts. I thought it was voltage regulator at this point, so I changed alternator. Same problems. Shows load and goes to no loads. Battery Still dies.
The only none factory item on the truck is extra fuel tank which has 12volt switch over. I just want to mention this so you'll have all the info.
Appreciated very much for your help. Thanks, Herb
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Wednesday, June 23rd, 2021 AT 6:58 PM (Merged)
Tiny
CARADIODOC
  • MECHANIC
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Hi herb duncker. Welcome to the forum. The voltage regulator lives in the Engine Computer, not the alternator, but regardless of its location, it is working properly. What you are seeing is it working to recharge the batteries after they've drained excessively. Many years ago we would remove the battery negative cable and insert an ammeter to measure the drain, but that no longer works because it takes up to 20 minutes for some computers to go to "sleep mode". During that time it is common for them to draw very high current that would damage most meters or blow internal fuses in digital meters.

Instead, you will have to remove fuses to see which circuit(s) are draining the battery. To kill them in three days requires a pretty substantial draw. That can be measured with test equipment with an inductive pickup that can be placed around one of the main battery cables.

In particular, suspect the Central Timer Module (CTM) is not turning off. That's the counterpart to Ford's very troublesome Generic Electronic Module (GEM).

Caradiodoc
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Wednesday, June 23rd, 2021 AT 6:58 PM (Merged)
Tiny
GOLDNUGGET
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  • 5 POSTS
Had the alternator and battery ck'd. Alternator is working fine and the battery passed the load test. Running at 14.0 to 14.1 v is normal as mentioned. My attention will be finding the 1.0 amp drain on fuse 51. Had look see under the steering wheel with the one panel removed and couldn't see anything that is Free Hand Module. Behind the radio?
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Wednesday, June 23rd, 2021 AT 6:58 PM (Merged)
Tiny
SCGRANTURISMO
  • MECHANIC
  • 4,897 POSTS
Hello again,

As both Steve and Doc said, the voltage regulator will bring the voltage down to keep the battery from being overcharged. Remember your vehicle's battery only has 6 cells in it, each one should hold a 2.1 Volts charge for a grand total of 12.6 Volts. I have a quick question for you, does your vehicle have the premium audio in it?

Thanks,
Alex
2CarPros
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Wednesday, June 23rd, 2021 AT 6:58 PM (Merged)
Tiny
GOLDNUGGET
  • MEMBER
  • 5 POSTS
No. It is all basic stuff. Radio/ CD player and speakers in the doors. I bought the PU used. Not sure what it now has and what it did have. It has a trailer towing package. That's it. All standard stuff. Thanks for heads up on the battery and alternator reminder. Still trying to find the drain on fuse 51. Was the Free Hands Module standard with all 05 Rams PU? What I can find on U tube that the FHM is a small metal box with a multi pin plug in the back of it. If so, I don't think I have one. I looked from HVAC to the driver side door under the dash.
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Wednesday, June 23rd, 2021 AT 6:58 PM (Merged)
Tiny
STEVE W.
  • MECHANIC
  • 12,869 POSTS
It is an option on them. If you have it the module would be on the passenger side to the right of the glove box. You would also have a special rear view mirror with microphones to allow voice controls.
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Wednesday, June 23rd, 2021 AT 6:58 PM (Merged)
Tiny
BIGBRIG18
  • MEMBER
  • 2 POSTS
  • 2004 DODGE RAM
  • 4.7L
  • V8
  • 2WD
  • AUTOMATIC
  • 320,000 MILES
I have a brand new battery, it keeps going dead. I noticed I am getting a buzzing sound coming from the instrument cluster. So I disconnected the negative battery cable and put a test light in between cable and battery and it lights up. Pulling all fuses including fuse 51 no change.
So I took a volt meter and checked for voltage at the disconnected negative battery terminal and found 6.2v. I removed instrument cluster and disconnected 26 pin gray connector and voltage went away. I looked at some posts and every one was saying horn pad. So I disconnected horn wire from pad and I still have 6.2v with cluster connected. So my best guess is the cluster has some internal short.
Has anyone ran into this problem?
Thank you
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Wednesday, June 23rd, 2021 AT 6:58 PM (Merged)
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 42,468 POSTS
Hello,

This is common when the clusters go bad. here is a video of the job being done in a similar car with instructions in the diagrams below to show you on your car:

https://youtu.be/_HEC44xENxw

This guide may help as well:

https://www.2carpros.com/articles/car-battery-dead-overnight

Check out the diagrams (below). Please let us know what happens.

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Wednesday, June 23rd, 2021 AT 6:58 PM (Merged)
Tiny
BIGBRIG18
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  • 2 POSTS
Thank you Ken.
I replaced cluster before I received you response and that did solve the problem. The video had good information, i'll keep that for the future. Thank you again for your help.
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Wednesday, June 23rd, 2021 AT 6:58 PM (Merged)
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 42,468 POSTS
Nice work, we are here to help, please use 2CarPros anytime.
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Wednesday, June 23rd, 2021 AT 6:58 PM (Merged)
Tiny
JOEZDAD
  • MEMBER
  • 2 POSTS
  • 2004 DODGE RAM
  • 5.9L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 119,000 MILES
I have a parasitic draw of a little more than an amp that I have traced to the center plug on the instrument cluster. Unplug center plug and no draw. Also the horn is constant on. Unplug center plug and no horn. Tried disconnecting the forward control module that houses the horn relay and also no horn. Still have parasitic draw. Pull horn fuse and also no horn. Still have parasitic draw. Took it to a shop and had an electrical expert look at it with no luck. He tried a used cluster with no change. Unlikely both clusters have the same problem but not impossible. Any help?
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Wednesday, June 23rd, 2021 AT 6:58 PM (Merged)
Tiny
WRENCHTECH
  • MECHANIC
  • 20,758 POSTS
I would suspect a TIPM here is how to replace it in the diagrams below. Check out the diagrams (Below). Let us know what happens and please upload pictures or videos of the problem.
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Wednesday, June 23rd, 2021 AT 6:58 PM (Merged)

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