2020 1500 EcoDiesel major electrical issue

[TommieT]

I have a 2020 1500 limited ecodiesel. Recently the electrical system has been acting whacky. It starts by making a loud thud. Sound like something hit my windshield. In fact it cause me to instinctively duck down yesterday when it happened. Only seems to happen with the truck stopped (thank goodness). So, I hear the thud (can't remember if I had turned off the ignition already or was in the process of doing so). My dashboard goes completely off. No lights, no nothing. I push the start button, it's dead. I try that a few times, no change. I open the drivers door, lights come on and dashboard lights come on. So, I close the door and push the start button. Now the truck starts. Having had this problem before, I put it in R to see if my backup cameras are working. In the past I'd get a blue screen saying cameras aren't available. Now, I get nothing. The screen still shows the radio screen and NO backup camera on the screen. I turn off the vehicle, go into the store to get my business done. When I come back, about 5 minutes later, the vehicle starts and the backup camera works, like nothing ever happened. This morning I get a message that says my vehicle will not start in 170 miles and I need to get the DEF system serviced by a dealer. I also have had this message before. (Yes, my DEF tank has plenty of fluid).
When I took my truck in for this problem a few weeks ago, all they could find was that the DEF pump pressure was too high so they replaced the pump and clamp to the tune of $1,700. Now I'm back where I started.
Does anyone have any insight to this?
T

 

[2021EcoDiesel]

Not to belittle the issue, but definitely test your battery. These modern vehicles do a whole mess of goofy things when the battery is low. I'd start with testing the battery and checking your battery cables, grounds, and the wire going to your starter. As well check your major fuses and make sure they're all in good shape and not loose in their receptacles, Battery Fuse, ECM Fuse, BCM Fuse, ETC...

The backup up camera not coming back on immediately is a side effect of a dead battery or a bad connection somewhere. (hopefully just a connection to the battery and not the body computer) When these trucks "boot up" from a battery replacement or disconnection, many features such as Climate Control, Backup Cameras, and Parking Sensors need several minutes to start back up and re calibrate themselves.

As far as the thud goes, it's hard to say anything without an audio recording of the noise, but maybe someone has had a similar loud thud when parked happen to them and can point you in some direction.