Radio & display inop after starting engine?

[DavidComeau]

2017 3500 (work truck) AUTO 2WD reg cab. Started engine and tried to turn on radio and just got a lit blank screen . No radio. No anything on screen. Still trying a few things and continue to push on-off volume button. Headlights on...go to store.
Drove almost 15 miles then saw a little yellow LED on the middle button heat control knob was AC on!
Turned AC led off then radio came on! Wow crazy computer?
Got home from grocery store and was going to back of bed to grab groceries and had burnt rubber smell checked both sides. Same smell Checked front wheel wells/tires-nothing.
different time:
Had error codes prior to Mass. inspection and it failed... only 14K miles? transmission low voltage? Cab no communication?

Hope to get some time this spring to work on my 96 2500 cummins auto regular cab. Only 234k until the injector pump screwed up. starts runs but engine won't pull

 

[RammerJam]

I'd look at batteries.

The burnt smell is most likely from a regen. Threw me for a loop the first time I smelled it, too

 

[JR]

If your truck sits for long periods in cold weather your batteries may be low. Lots of electronics that dont totally go to sleep.

Did you notice a message in the EVIC when you first started it?

 

[DavidComeau]

If your truck sits for long periods in cold weather your batteries may be low. Lots of electronics that dont totally go to sleep.
Did you notice a message in the EVIC when you first started it?

Electronic Vehicle Information Center! looked it up

OK checked a few minutes ago:
Turn key on
go to evic
go to voltage, 11V-I'm surprised!
turn key to on for preheat delay
voltage drops to 10v
After crank/start+ 10-15 seconds it goes up to 14 from alternator charging.
This truck is a 17 but bought new off lot in Kernersville NC Nov 18. I had looked at the battery date since I knew just sitting is bad for batteries. They had been changed?rotation with newer ones. So now only a little over 2 years and batteries questionable?

My 96 is now on my 3rd set of batteries, but they are now dead but were usable last summer.

 

[JR]

If it sits for extended periods it will drain new batteries. Too many modern gadgets that stay awake. Irun a NOCO tender during the winter if it sits more than 5-7 days. I dont worry about it too much during the summer because I run it quite a bit more.

Your best bet is put a charger on your current batteries on as low a voltage as possible for several hrs depending on voltage. Then disconnect cross over cable and load test each battery independent of each other.

 

[DavidComeau]

Thanks JR
Pretty sure the 3500 very rarely goes over a week without running. It is my only vehicle (running/registered). Even with covid, I still go to the post office, credit union and grocery store but that's the majority.
I'd get easy 6-8+ years on my 96 with no battery tender. Owning and running this 17 seems way more problematic than my 96. I finally pulled the plate off the 96 and transfered it to my 67 Lotus and hope to have it for a second set of wheels by this fall.