2003 parasitic battery drain

[Wetwillie]

Recently my 2003 LC has not been starting after sitting 3 days. it's a healthy battery but when tested with a meter after it wouldn't start only showed 3.5 volts.

Brought it to my shop and they pulled all the fuses and finally found a fuse to a control unit? , and said there are 40 more fuses that run through this control unit?

My plan is to bring it back next week.

Anyone else ever have this problem or ideas what may be going on?.

I did check all the usual suspects, interior lights, stereo etc.

 

[e9999]

first thing might be to figure out how much drain there is. If you don't, maybe a friend may have a suitable meter or a shunt resistor? You could then check individual circuits for leakage too.
I imagine you have tried charging fully the battery and then immediately trying to crank the engine to see if starts OK?

 

[Wetwillie]

first thing might be to figure out how much drain there is. If you don't, maybe a friend may have a suitable meter or a shunt resistor? You could then check individual circuits for leakage too.
I imagine you have tried charging fully the battery and then immediately trying to crank the engine to see if starts OK?

The shop measured the drainage . It was like .5 and the shop said it should be .2

I jumped it with a portable starter pack, started right up.

What is circuit leakage? how do you measure it?

 

[e9999]

0.5A is a lot. Even 0.2A. So, yes, there is likely something odd going on.

I went outside for you and measured the drain on my 2003 for reference. The battery was very low (11.9V) so this is maybe a bit off compared to a fully charged battery, but I got about 50mA (varying from 30 to 70 really because that is an iffy measurement) drain off the battery. IIRC that is pretty standard.
I'll try again with the battery topped off.
When I said circuit leakage I meant to try each circuit individually with a meter for parasitic current loss. Ideally you'll want a clamp DC ammeter, there are some decent ones not too expensive (<$50). Very handy around the truck.

added: measured drain again at 12.65V and it was the same 50mA or so.

 

[Wetwillie]

Thank you for going through the trouble of measuring. Now I have a baseline..

 

[abuck99]

There are a few threads on the forum pointing to sources of “parasitic battery drain”. A common one: If you have the overhead drop down screen with DVD player in cargo area this is a common drain point as it is always live. Fuse is located directly under the glove compartment support.

You can get a multi meter at HD, Lowes or HF (HF has a $10 cheapo that works well enough)

Here’s a couple of different how to videos on checking for parasitic drain- that hopefully saves you some diagnostic $$. When you isolate the problem circuit- post back here with result.

 

[Wetwillie]

There are a few threads on the forum pointing to sources of “parasitic battery drain”. A common one: If you have the overhead drop down screen with DVD player in cargo area this is a common drain point as it is always live. Fuse is located directly under the glove compartment support.

You can get a multi meter at HD, Lowes or HF (HF has a $10 cheapo that works well enough)

Here’s a how to video on checking for parasitic drain- that hopefully saves you some diagnostic $$. When you isolate the problem circuit- post back here with result.

Thank you for taking the time to post the link and the info.. I have that HF meter already, so I will do some testing.

First thing is unplug the DVD player that has not been used since 2010 .

 

[abuck99]

I just edited my post and linked another video that I think offers a little better instructional content.

 

[e9999]

that vid with Eric the car guy is pretty funny. Much of what he's saying makes sense, actually, but his roleplaying is kinda weird. Going through all that troubleshooting to conclude that the dome light is on... LOL

and, yes, the other vid (the humble mechanic) point that it is faster and arguably better to check the draw on the fuses outside contacts is good, but of course that assumes your fuses do allow that, and I would be hesitant to put too much faith in the numbers at low draw.

Then again, the (relatively speaking) good thing about all this is that if you have a big enough draw to cause problems, then it is likely easy to measure and see one way or another, cuz it's -well- big...

 

[Wetwillie]

There are a few threads on the forum pointing to sources of “parasitic battery drain”. A common one: If you have the overhead drop down screen with DVD player in cargo area this is a common drain point as it is always live. Fuse is located directly under the glove compartment support.

You can get a multi meter at HD, Lowes or HF (HF has a $10 cheapo that works well enough)

Here’s a couple of different how to videos on checking for parasitic drain- that hopefully saves you some diagnostic $$. When you isolate the problem circuit- post back here with result.

Spoke to the mechanic.. The draw was .55- He said when he pulled the fuse for the ECMB2 that that eliminated the draw.

He says that the ECMB2 is the fuse for many other things in the truck and he has to manually unplug 30-40 things to find the culprit- brake booster-radio etc

Is there typically one thing that fails that is connected to the ECMB2 that we can start with to streamline the process and find the culprit?

 

[e9999]

you may want to get the wiring diagram for your truck?

 

[abuck99]

Here you go

EWD- 04 Electrical Wiring Diagram

 

[Wetwillie]

Here you go

EWD- 04 Electrical Wiring Diagram

Thanks..

 

[RPLX470]

Here you go

EWD- 04 Electrical Wiring Diagram

Great info. Thanks. This would apply to a 2003 also?

 

[abuck99]

Great info. Thanks. This would apply to a 2003 also?

May not be exact but should be very close

 

[mmbirtcher]

Keep an eye out for electrical gremlins. Little things that don’t quite operate exactly as they should. For example, my wife’s Tucson had this problem and I noticed one of the power lock switches was slightly out after power locking. It was draining the battery trying to lock the door overnight. No sounds or anything. So any slight electrical changes may give you a hint as to what the problem is also.

 

[jerryb]

he means ecub2 right? unplug the nav under the ass seat. 9 out of 10 this will be it.
then windows, door locks and seatbelts. not in any order.
then back up cam ecu also under the pass seat.
if you were in an accident or someone has worked on those circuits lately then it could be anything.