Need help please possible wiring issue

[Jessyfew]

Hi guys new here I’m hoping to get some help. I have a 2019 ram 2500 big horn diesel. My four wheel drive switch sometimes doesn’t light up. When it doesn’t light up it obviously doesn’t work. But then it will come on sometimes. I left it sit for 2 days and went to start it an the truck appeared to be “dead”. Charged battery’s and tested them under load. Battery’s we’re fine. Cleaned terminals an connected them. Truck started but had 5 codes. B2199,C3100,C211b,C212a,C0020. I cleared the codes. Truck is still starting as of right now but when it starts it draws the voltage down to around 11.5v then slowly climbs. Any insight would be greatly appreciated. It is out of warranty by the way.

 

[Richard320]

You may have better luck over at https://hdrams.com. The 2500s are totally different from the 1500s electrically.