The battery isn't holding charge while parked. I can watch the voltage drop fairly quickly - within an hour it will go to 11.8v. I have to jump it if it sits for a day.

Quick stats:

• 2000 V10
• 3 month old battery
• New AC Delco alternator
• Battery tested good today at local auto parts store
• I am doing all testing with truck locked, driver's door latch closed, waiting 40mins
• No after-market or DIY electrical accessories on my truck

When I pull fuse #105 under the hood, that seems to cause the draw to stop completely. I'm seeing ~11volts at the fuse with a multimeter. This is called "Junction Box Battery Feed." What exactly is this? Does it just go to the under-dash fuse box?

In the under-dash fuse panel, I only see two fuses drawing:

• #14 at 109mA (Interior lights, etc)
• #15 at 96mA (GEM, PATS)
• (These were calculated via voltage drop using a fuse voltage drop chart to calculate mA)
• No other fuses drawing any power (via voltage drop test)

Pulled only fuse #14

• Battery 12.27V --> 12.06V in 45mins

Pulled fuse #15 as well (#14 and #15 pulled together)

• Battery 12.06V --> 12.06V in 20mins

Fuse #14 back in (only #15 pulled)

• Fuse #14 not showing any voltage on a voltage drop test any longer
• Fuse #105 still showing a large draw
• Battery 12.06V --> 12.00V 55mins later

One other thing I forgot to mention - when I start it and I can tell the battery is low, but it ends up starting, the THEFT light will be blinking on the dash. If I jump it the THEFT light usually blinks as well. After a few minutes it ends up going away.

 

How do your terminals look? Grounds clean?

 

Terminals look good to me. By grounds to you mean finding all the ground points and making sure they are clean? Would I just follow the negative lead? The couple ground points I see near the battery look fine but I didn't follow it back...

Yesterday I removed the GEM and cleaned all the contacts and the fuse panel contacts with CRC Contact Cleaner. When I plugged everything back in it was at 11.87V. 1.5 hours later sill at 11.87V. Turned key on ignition off, and locked everything, and it was at 11.60V

Next day (today) it is at 11.37V, so not too bad of a draw. Hopefully the GEM pulled a little power and then went to sleep. I put the jump pack on and started it, and it only used 1% of the jump pack battery. I'm hoping that cleaning all the contacts made an improvement. It wasn't very dirty or corroded though. I'll see how easy it is to start tomorrow morning... probably won't drive at all today.

 

Pull your ADR relay and see if it draws down overnight

 

I have always used an amp meter vice a voltmeter to track down parasitic battery drains. Most multimeters have an amp function. I use a separate DC digital amp meter I got from Amazon. I connect it in series with the + terminal and then pull each fuse until I find the culprit(s). Then I go to the drain source and disconnect it. I insert the fuse to see if it is a component failure or a wiring issue. On excursions it can take a while to isolate the problem. If fuses are not the problem, the next step are the relays.

Ed

 

Fuse F105 feeds the under-dash fusebox.

 

I see that universal terminal on your negative side, not a fan of those. I would replace with the OEM style terminal.

 

ADR relay pulled made no difference.

My multimeter's amp function wasn't working, so I was having to go by voltage. I just got a new one, and I am seeing 250mA. When I pull the fuse #15 it goes down to 8mA. If I plug the fuse back in, I hear some clicking and it goes back to 250mA.

What I am confused about, is that I understand I need to give the GEM time to go to sleep. But if I unhook the battery, then connect my multimeter, did I just wake it up by doing that? Do I need to leave my multimeter on for 45 mins and then do my testing? And when I plug the fuse back in, won't it "re-awaken" it?

Anyways, this seems to go exactly with this YouTube video - he mentions seeing a ~230mA draw that goes away when the GEM fuse is pulled. I am wondering if I just need a new GEM? Or is something else awakening the GEM? Again, when I pulled the GEM and cleaned it, it didn't look corroded at all. I'm not seeing any evidence of water intrusion, so I don't understand why it would be shorting out.

 

You need to connect the ammeter in series with the circuit. Then, IF YOU BROKE/MADE THE CONNECTION, walk away for 40 minutes without touching anything. Then make your reading.

it is completely normal of the GEM and its loads to initially draw a quarter amp initially. Once everything goes to sleep, anything under 50 mA is okay.

 

Thanks, yeah I realized that after I made that post. So I left it with the ammeter in circuit for over an hour. When I came back it was reading .01-.02A. Not sure if my battery is too low at this point to do valid testing? It is at 11.2V since I didn't drive it today.

 

Charge the battery and try again just to verify. but those readings are normal.

FWIW, I went through a number of the yellow-labeled batteries a while back with similar symptoms. The problems went away when I quit getting batteries with those yellow labels. Probably a coincidence....

 

Simple Disconnect for long term storage or until you discover parasitic drain

 

I think I found the issue. Seems to be a short somewhere on the circuit for fuse 14.

When I leave the vehicle locked I can see the voltage on fuse 15 drop down significantly after 1 hour. But fuse 14 shows voltage, when it shouldn't at all. At least, judging from what is listed on this fuse (basically interior/running board lights, mirrors, power windows).

If you look back at my first post, what is odd is that I see voltage of the battery drop when fuse 14 is in, but fuse 15 pulled. So fuse 15 for GEM doesn't seem to be a factor.

For the last few hours, I've had fuse 14 pulled and the battery has been stable - hasn't lost a single .01V

So now, I guess I have to find the short on fuse 14... seems like the hard part. Nothing obvious I can find - no lights left on or anything. In fact I can turn on every light one by one and watch voltage on fuse 14 increase, but there is still something pulling power when all lights are off. Same for mirrors - if I make a mirror adjustment, voltage on the fuse increases for a second then drops back down to the baseline voltage being drawn. Only guess I have at this point is water intrusion on the running board light sockets so some kind of short there? Is there any easy way I can basically remove the running board lights from the circuit? I can't seem to find a wiring diagram online anywhere.

One other thing, is my mirrors are aftermarket Trail Ridge "new style" tow mirrors from 1A Auto which are about 2 years old. The covers on them don't quite snap in completely, so perhaps there is water intrusion there and they are pulling power also. I guess I can take off the door panels and disconnect the mirrors to rule them out.

At this point I am almost ready to just pull the fuse and live with it. I hardly ever use the cargo lights, never use mirror adjustments, and pretty rarely have to roll down my window...

 

Are you referring to the Walmart batteries?

I personally use the Costco Interstate, 36 month warranty now.

If you have an Interstate store near by, they sometimes have sale prices too.

 

That's probably an incorrect conclusion. In post #9, you reported a result that is normal behavior. If your current THROUGH F14 drops to a negligible value after the 40 minutes, the battery saver circuit is working normally and you're down a rabbit trail.