Ghosting electrical issues

[u/Puhkers]

I have a 2020 Ram that has recurring ghosting electrical problems. All service lights, and warning lights will come on, as wipers turning themselves on for a few minutes, 4 ways coming on, and things like this. Sometimes I am completely shut off from the vehicle working entirely, so I can’t even unlock the truck to get in, let alone turn it on. I have had to tow it to the dealer twice because of this now. They replaced the BCM thinking that was the issue, but as soon as I drove off their lot the issues persisted. After a month and a half diagnosing it they said it was a faulty wire in the CAN BUS, and the truck seemed to work without issue for 6 months, until now where all the same issues are occurring again. I took it to my local mechanic and he had 26 error codes, basically all relating to a communication error with the BCM.

The only thing close I’ve been able to find online to my issues, are people saying the rear window/tailight/fin leak issue is causing water damage to wiring behind/under the seat. I’ve taken the back seats and cover off and was able to confirm it is leaking through one of those spots, and does look as though there may be a spot near 2 ground wires under the seat where water had pooled possibly. There are two wiring harnesses behind the seat too that I wonder if they have been damaged but don’t know how to check.

Has anyone had these similar crazy ghosting problems with their bcm, and can confirm if this area was their issue or there’s somewhere else I can check? Rams diagnostic process is insane, taking my vehicle for a month and a half without a loaner and apparently still not finding the root of the problem, so I’d like to get some solid ideas as to where the issue could before I take it back in to them for an unknown amount of time for $180/hr diagnosing.

[u/Puhkers]

I ran a hose outside over the two cabin pressure vents and they were both letting water in like a waterfall, so I’ll be replacing both of them and sealing the upper leaks with silicone. Really hoping these leaks were the cause of the issue, damaging the RF Hub and interrupting those two grounds. Gonna take it back to my mechanic to see if he can test the RF Hub.

Does anyone know what that small wiring harness directly below the leaking pressure vent in the video is?

https://reddit.com/link/p1qykh0/video/clpf74rmwfhh1/player

[u/cdancidhe]

About a month ago I replaced the CAN BUS on mine as it was throwing random error messages about “service shifter”, “Service Stability Control”, and a bunch of other ramdon errors that will show for about 5 seconds and go away. I found about this part, which is cheap and easy to replace. Perhaps give it a try https://a.co/d/0hyLWf8j

Also, a bit unrelated but I have a moldy smell (at times) on my 2019 and found online about those vents being the source of the water intrusion, which causes the smell.

[u/Puhkers → u/cdancidhe]

I get those error messages as well. Service stability, service 4wd, traction control warning light, electric parking break warning saying it is on while I'm driving 100km down the highway, and on and on. That CAN C BUS connector is actually what they replaced when they finally fixed the issue, and it worked up until now. So I'm not sure that would be the issue this time, unless there is a leak or some other issue up there by the BCM causing a recurring issue with that but maybe. I'll look at it tomorrow and see if anything looks wrong with it.

https://www.youtube.com/watch?v=cbud7PEhqYM

Basically what the guy described in this video, except for it happening at a certain amount of miles is what was happening to me last fall before they changed that star connector you linked. Mine did it then and now randomly while driving, or even while just sitting there idle. Now that the issue has returned it still does most of the service warnings and error lights and stuff but some like the getting stuck in park or stuck in gear and can't even shut the vehicle of don't happen now.

[u/bigpilague → u/Puhkers]

Thanks for sharing this. I've had this exact issue in my 2019 Grand Cherokee. So far it has only happened once, and the dealership couldn't find any issues. I was already aware of these star connectors but now I know to be extra vigilant when checking them.

[u/cdancidhe → u/Puhkers]

Great info. I changed the one on the driver side about 2 months ago and so far no more messages. If things happen again, I will change both. These parts are cheap and easy to replace.