Parasitic Battery Drain

[wyosteve]

The truck is constantly 'searching' for the key fob so it will drain the batteries.

 

[Ozymandias]

Is your truck up to date software wise?

I can say for sure that something is wrong with it and not in proper working order, now you can do some bandaid fixes like pulling fuses - or have it fixed. I think it will be hard to do that yourself without diagnostic equipment like wiTech that a dealer will use.

Aside from that I can't offer more help here as it needs hands on work.
Your truck is stock-stock that means it is in its own systems, that's why I asked you the questions above.

 

[Turbo Terry]

Thanks things I did not know

 

[Tuesdak]

It might have just been my imagination, but it seemed like even this summer the starter turned a bit slower than I remembered so maybe the batteries were going. bad then already.

The nice thing about AGM's is you only need one good one to start the Cummins. If you suspect it's cranking slow you need to immediately charge and as soon as practical load test the batteries. One bad battery can drain the other battery 'dead' overnight. Again if you have the thought "it's cranking slower..." Bluntly: it is and action is needed.

I just went through this on my 2018. I suspect the 2018's are programmed by a ex-GM employee and stuck on "slow float charge" 13.X volts vs. the get em charged, NOW: 15 volts my 2003 would spit acid out of the batteries at...

https://www.turbodieselregister.com...-a-5-year-warranty.270960/page-2#post-2706314

 

[wyosteve]

Well, new batteries did the trick and it fired right up, but I'll start watching the voltage for a while and see if something seems amiss. One last question-in terms of a solar tender, do I need one or two? If just one, which battery should it get connected to so that it trickles over to the other one?

 

[Ozymandias]

The batteries are a unit and act as one, doesn't matter which one you connect to as it is one.
That's why a bad one can kill the good one.

 

[wyosteve]

Thank you Ozy!

 

[Topzide]

That's where hooking a battery tender through the 7 way is great, you don't need to open the hood to connect. If using a solar tender, use the 12v power outlet that can stay powered with truck off.( may need to change fuse position for that) Glad to hear that the new batteries fixed the issue. Just watch for any drain.

 

[AH64ID]

My ‘18 would drain the batteries in 2 weeks, which is why I used a NOCO Genuius 5 on it when parked form more than 3 days.

If I were to park at a trailhead for more than a week I’d pull the IOD fuse, and I also carried a jump starter battery pack.