[tmhd82]

I left my truck in the garage for just over a week while I was out of town, and came home to find it stone cold dead. I haven't been able to diagnose anything yet because it's still on the charger, but you can certainly color me surprised - my 98 Mustang that only comes out on nice days sits for weeks at a stretch routinely, and it's never failed to start. Same for my old lifted up Grand Cherokee that is strictly an off road toy at this point. So what gives when it comes to parking my 1 year old Chevy? :???:

Nothing was left on, and I don't have any aftermarket electronics, etc. The only thing I left plugged in while I was gone was my USB thumb drive with my music library on it.

Has this been an issue with these trucks, or am I just really lucky? I'm super glad this was in my driveway and not in an airport parking lot.

I'll follow up once I (or the dealer) figure it out.

Thanks,
Tom

 

[Brayan Rosales]

make sure you have tight connections, I have a inverter hardwired into the battery, always on even if the inverter switch isnt on and I have not had this problem

 

[Chuck_B]

Do you have a DMM with a DC millivolt range? The micro-fuses (and possibly others) in the panels have small exposed electrode tabs on their top surface. One probe to each tab and you will be measuring millivolt drop across the fuse element.

Don't pay any attention to polarity, that's just a matter of how the probes land.
The higher the millivolt reading within a given fuse size the higher the current draw on that circuit.

If you want to convert the millivolt reading to actual current draw - see the following charts, or those provided by any other fuse vendor:
Fuse Charts Download

I would probably go through both fuse boxes recording the highest absolute value for each fuse size and then estimate the max current for each group from the linked charts. To cause an issue of this sort you would have to bleed around 50 Amp-Hour over the week. Look for a 300mA draw or more to accomplish that. The difficult part will be ensuring no dome lights or electronic systems are temporarily running because a door was opened.

...Or - You could always take it to a dealer...

FWIW I don't seem to have any such issue with my '16 Dmax

 

[n9cv]

I went through this a few years back and during the process I found their engineering was the their design point is .020 amps or 20 ma. Their design point also was that any vehicle must be able to sit for 30 days and still start. The second spec spec along witha few other factors determined the minimum battery size required. When I started looking for mine draw it was slightly less than 400 ma. After I found problem it now is 18 ma.

Anything that keeps the BCM awake will cause the problem. In my case it was an aftermarket inside mirror that I had taken power off of a dome light. Well the interior light circuit is monitored by the BCM and with draw from the mirror the BCM stayed awake thinking that the door was open. Changing the power source to a non-BCM monitored circuit fixed the problem.

 

[tmhd82]

Thanks everybody for all the advice. Finding electrical draws is a process I'm very familiar with due to my years as a Jeep owner. Grand Cherokees have a nasty problem with this...

My inquiry here was more to find out if anybody else had experienced this problem with these trucks.

Just an update that I charged the battery and have been driving the truck all week. It's been a busy week and I haven't really had the time to look into it yet, but it appears to be drawing pretty significantly when it sits overnight. This morning I turned the key to run and looked at the voltage display before starting the truck. It was at 11.6 volts. Truck started just fine and was charging at 14+ volts for my 15 minute drive to work. My volt meter was within a few 10ths of the dash gauge when I resurrected the truck the other night, so I'm inclined to believe that the dash gauge is pretty accurate.

I'm going to dig into it a little bit to see if it's something I can fix more easily than dealing with the dealership. If not, it becomes their problem. God bless a warranty!

Tom

 

[blue47]

You could have a weak/failing battery.

ron

 

[ernster500]

For what it's worth, I have a 2016 DMax with no after market electronics or lights. One flash drive plugged into the USB and a USB Charging Port with an LED light plugged into the outlet. I've left my truck for up to three weeks at a time with no problems what-so-ever. Hope that doesn't mean you are the unlucky one...

 

[tmhd82]

Looks like it's the battery. Truck is drawing .03 amps after everything goes to sleep.

Now I just need to find time to take it to the dealership...