parasitic battery draw

[hikethemtns]

my 03 3500 has a parasitic draw that will run the batteries down over a week, i've pulled the fuses one at a time and disconnected alternator while watching a test light connected between battery post and terminal, light stays light, thanks in advance for any help.

 

[04blackcherry]

Have you had the phantom honking horn issue? Anyway there are some things that pulling fuses doesn't cure the electrical draw. In my case, I had to disconnect the horn from the system rather than pull the fuse. The control module would try to honk the horn even though the fuse was disconnected. The electrical draw was the control module.

 

[Wingate]

If its taking a week, and you have two good batteries, you might look close at any added electrical equipment such as an aftermarket amplifier, hands free device, etc. .

Other than that, I would look for a glovebox light, dome light, courtesy door light. (I've actually found this one before)

Take a GOOD DVM and disconnect one battery, then remove the + on the other battery and put the meter inline with the leads plugged in for checking DCA. Prop the meter up so you can watch it and start disconnecting stuff until the amp draw drops.

There will be some parasitic amp draw... but it should not be much.

 

[BGlidewell]

hikethemtns,
not sure I agree with your test setup. I would use a clamp-on ammeter around a battery ground and start disconnecting.

 

[jelag]

Lets look at this another way. . these are 100 amp hour batteries... 1 amp for 100 hours each or 100 amps for 1 hour... . a standard measurement of current in batteries... .

A week is 168 hours... 200 amps divided by 168 is a little over 1 amp... something most clamp on DC amp meters won't read well... . I own 2 of them... . both high end units and I wouldn't trust either of them to read that low of draw.....

OTOH - I'd install a 15 amp mechanical amp meter (under $15) in either the ground or 12+ side once I'd opened the doors and taped the door switches closed... . and than start the test... . this low range meter will show that 1+ amp draw and than you can find it... .

I now have stored a 05 3500 dually and a 1 amp trickle charger will in fact keep it fully charged and I've let it sit for 2-3 weeks with no problems..... I agree with the guys above... something you've added to the truck... . or one of the computers has excessive draw...

I also own a high end scan tool, and am sitting here wondering if that will read whats on when the truck is off... . I'll have to look at the manual... . something I've not thought about... .

 

[cerberusiam]

The computers have a constant draw on the batteries and its normal. The ECU retains things in memory as do the other processors. These trucks ship from the factory with all this turned off or they would arrive with dead batteries. A trickle charger is the solution if possible.

 

[Prairie Dog]

There is a constant draw on the batteries from the computers but mine sits for 2 weeks at a time and then starts right up, even when the batts were old there was no problems. So, I dont think its the puters unless something is wrong with them

 

[Dbonzi]

my 03 3500 has a parasitic draw that will run the batteries down over a week, i've pulled the fuses one at a time and disconnected alternator while watching a test light connected between battery post and terminal, light stays light, thanks in advance for any help.

How old are the batteries? This is what happens to mine when the batteries are getting old. One will have a standing charge of 12. 3V and the other will have 12. 6V, The low or bad one will discharge the good one over time. As they get older the time becomes less and less.

Dennis

 

[JMetzger]

My 02 still has the original battery's & it sometimes sits for a month at a time & when I go to start it up it fires right off.

 

[RMacneil]

hikethemtns,
not sure I agree with your test setup. I would use a clamp-on ammeter around a battery ground and start disconnecting.

The clamp-on ammeters are not good for detecting parasitic drain. The draw you are looking for is usually very small. It's more accurate to disconnect the positive battery cable and connect a DMM in-line between the battery positive post and the positive battery cable (bridging the the connection) set the DMM to DC A. Disconnect the ground on the other battery that's in parallel.
Make certain all lights, accessories, and ignition are off. Close all the doors and make sure all courtesy lights are off. Wait 10 minutes for all the computers and circuits to power down (they actively watch for a while, you will see them drop off on the DMM) You should see:
Normal 10-30mA (0. 02 to 0. 03A)
Max= 50mA (0. 05A)
Anything higher than 50mA is going to tax your battery.
If you have a high parasitic drain, pull each fuse, one by one, watching the meter, until the draw goes away. DO NOT REPLACE A FUSE AFTER IT'S REMOVAL- this will cause computers to "wake up" rendering your test inconclusive.

As mentioned, be sure to verify that health of your batteries. 12. 6V is a fully charged battery (2. 1V per cell x 6). If your batteries are in question, isolate them and load test them for 15 seconds w/ a carbon pile load @ 1/2 the CCA rating. If they drop below 9. 6V, they are not strong enough for service. Check electrolyte levels (if equipped) and try to recharge them separately. Make sure there is no corrosion on the cables, posts, and connectors. Also... keep the tops of your batteries clean. They WILL self discharge across the dirt and moisture resting on their tops.

Good Luck.

 

[nutter3]

I agree with Prairie Dog. I often leave my truck sitting for more than 2 weeks. It always fires right up. So you must have more of a draw than normal.
Good post Rmacneil.

 

[Mishkaya]

I'll throw in my . 02...

I have an '05, purchased new that developed the parasitic draw issue. Traced it down to the instrument cluster. Haven't bothered to replace the cluster yet as we just remove the fuse in question (don't remember off-hand which one it is). There have been a few others with the 3rd gen trucks with this same issue; most of us however have the ghosting bright light indicator, and it is caused by a bad ground somewhere in the cluster. In my case I have a . 9 amp draw unless the fuse is pulled. Normally the draw should be about . 02 amp I think.

There have been a few as well with the drain coming from the factory stereo, and the issue went away when it was replaced with an aftermarket unit.

Might want to check those two first.

 

[seafish]

I'll throw in my . 02...

I have an '05, purchased new that developed the parasitic draw issue. Traced it down to the instrument cluster. Haven't bothered to replace the cluster yet as we just remove the fuse in question (don't remember off-hand which one it is). There have been a few others with the 3rd gen trucks with this same issue; most of us however have the ghosting bright light indicator, and it is caused by a bad ground somewhere in the cluster. In my case I have a . 9 amp draw unless the fuse is pulled. Normally the draw should be about . 02 amp I think.

There have been a few as well with the drain coming from the factory stereo, and the issue went away when it was replaced with an aftermarket unit.

Might want to check those two first.

Two questions then--



1) What part of the instrument cluster does not work after you pulled the fuse that fed the cluster circuit??



2) Can you tell us which number fuse that you pulled to correct your cluster draw issue?



TIA

 

[Mishkaya]

Two questions then--



1) What part of the instrument cluster does not work after you pulled the fuse that fed the cluster circuit??



2) Can you tell us which number fuse that you pulled to correct your cluster draw issue?



TIA

Here's the weird part: everything in the cluster worked with the ignition on as far as I can tell, even with the fuse pulled. It would seem that the cluster monitors things when the truck is off from what I was told, those things were disabled. I remember that the remote keyless no longer worked at all. I am no longer the one driving this truck daily, so I will have to inquire as to which fuse it is and report back.

 

[seafish]

Here's the weird part: everything in the cluster worked with the ignition on as far as I can tell, even with the fuse pulled. It would seem that the cluster monitors things when the truck is off from what I was told, those things were disabled. I remember that the remote keyless no longer worked at all. I am no longer the one driving this truck daily, so I will have to inquire as to which fuse it is and report back.

Thanks!! That is kind of wierd, I wonder what the cluster or ecm monitors when the ignition is off... ??



Anyway, since I own a 2005 also, it would be grert to know which fuse you had to pull the kill the parasitic draw on the cluster... . obviosly it would be a good place to start if my truck ever starts to exhibit battery issues. Right now, ( knock wood) still on the oems at 67k !!!Oo.

 

[Tejasdge]

I played the chase game as well when my truck would go dead overnight on 1 year old batteries. I used about every kind of ammeter including the $15 mechanical and tore the heck out of the loom, pulled every fuse and disconnected most every connector. I finally retested the alternator that tested fine before and it was barely hanging in there. On the psuedo useless dash voltmeter it was running above 14 volts. I opted for a mega amp alternator and love to watch it do battle with the grid heaters. It stays at 14 volts all the time.



I think if I replace the brushes on the old one, it will be a good backup because they are pretty bad. I drove the truck for several day by charging the batteries after the trip. We had a cub scout campout that weekend and I drove about 2 hours on it before charging. I think the alternator was eaking out a bit of a charge.



Good Luck.