Catastrophic ECU/PCM and/or infotainment system crash--what to do?

[Lamarsh]

I had the issues as you described with the windows...like u said fronts didn't work backs did,along with my radio doing weird stuff....so I started searching came across things from this and another forum.
Found out all of that stuff is/goes through the bcm,rears work due to something about it being wired directly and not through the bcm if I remember right.others can chime in on this as I only know what pertains to me.
Your codes said it lost communication with a few items.
I read online somewhere the dealer has equipment to test it..true or not I don't know.
You stated disconnecting the battery and things worked for awhile then started failing again(intermittent) ,reason I said that.
My radio has the phantom screen station changing every once in awhile now...truck to old to me so im not fixing it.Unless someone on here has an easy cheap fix???
I'm certainly no tech/mechanic on this newer stuff,just throwing things out there for you to check or have checked,theres fellas on here way more knowledgeable than I about all this stuff but short of the vehicle sitting in front of them with equiptment/scanners and whatnot hooked up is difficult to diagnose sometimes.
I hope you get it sorted out and let us know the fix.

Thanks. Sounds like a similar issue. A close friend of mine is one of the top engineers at Ram, and one thing he said to me was the fact that this issue reared its head when the truck was 4.5 years old makes it likely it is a wire that is out of place, came undone or even chewed by an animal (we have pine squirrels here, and they do sometimes get into engine compartments, but my truck has no evidence of that as far as I can see, they usually leave a lot of evidence they there).

I'm trying to get a hold of an analogue toaster style battery tester today so I can try to rule out the battery issue that some folks mentioned above. If that doesn't work, I'm taking it in.

I will keep you guys posted. I appreciate everybody's input. Whatever ends up happening, I will post the progress/outcome here in hopes this could help others with similar issues.

 

[Lamarsh]

Add me as another commenter suggesting a charging system test. Typically a battery has 12.5 volts with the engine off. Start it up and you’ll typically see mid 14V. A load test will check the battery and alternator output. It is essential that you have the proper voltage for the electronics to operate properly. A slight drop in voltage will cause random faults and wacky operation on the various systems.

The other posters suggesting the old school load testers are on to something. If you search why analog testers have an advantage the first thing you’ll find is digital testers do not measure fluctuations as well as the old fashioned analog type. Fluctuations are what you are looking for.

If you throw in the towel and take your truck to an automotive electrical shop the first thing they will do is test the battery/charging system. It’s the very first step in diagnosing the problem. Many folks will dismiss the battery because it still starts the truck or it’s only two years old. Batteries fail even when brand new and a 11V battery will start the truck most of the time. If your present battery is still under warranty it pays to test it old school and use the warranty before going down a potentially expensive rabbit hole.

I already have tested it twice with sophisticated digital testers and everything was normal, but I have yet to use an analogue one. I'm trying to do that today. My battery diagnostic on my instrument cluster says 14.2v most of the time while driving. The load it showed on the digital tester showed the same, with a slight jump up during ignition.

 

[Lamarsh]

I just had a guy at an auto parts shop (so take it with a grain of salt) tell me that it's possible that the security bypass cable I had attached to the OBD2 port could have caused this, and it may have partially fried my BCM. I installed the security bypass cable in order to be able to use the Alpha OBD program for one single thing, to change my tire size when I bought 35" tires. I did leave the security bypass cable in, and never removed it. He thinks that may have caused this. I'm skeptical, it's been connected to my truck now for 3 years and never was a problem, but who knows.

Now I need to find a way to remove it to see if that helps, but I can't figure out how to remove it from the wire harness board. It plugged in super easy, but doesn't seem to want to come out when I pull it. Pic of the cable I'd like to figure out how to carefully remove is attached.

 

[Tulecreeper]

I just had a guy at an auto parts shop (so take it with a grain of salt) tell me that it's possible that the security bypass cable I had attached to the OBD2 port could have caused this, and it may have partially fried my BCM. I installed the security bypass cable in order to be able to use the Alpha OBD program for one single thing, to change my tire size when I bought 35" tires. I did leave the security bypass cable in, and never removed it. He thinks that may have caused this. I'm skeptical, it's been connected to my truck now for 3 years and never was a problem, but who knows.

Now I need to find a way to remove it to see if that helps, but I can't figure out how to remove it from the wire harness board. It plugged in super easy, but doesn't seem to want to come out when I pull it. Pic of the cable I'd like to figure out how to carefully remove is attached.

View attachment 544622

Have you tried squeezing top/bottom or side/side on the plastic plug while pulling/wiggling it?

 

[Atcer2018]

I just had a guy at an auto parts shop (so take it with a grain of salt) tell me that it's possible that the security bypass cable I had attached to the OBD2 port could have caused this, and it may have partially fried my BCM. I installed the security bypass cable in order to be able to use the Alpha OBD program for one single thing, to change my tire size when I bought 35" tires. I did leave the security bypass cable in, and never removed it. He thinks that may have caused this. I'm skeptical, it's been connected to my truck now for 3 years and never was a problem, but who knows.

Now I need to find a way to remove it to see if that helps, but I can't figure out how to remove it from the wire harness board. It plugged in super easy, but doesn't seem to want to come out when I pull it. Pic of the cable I'd like to figure out how to carefully remove is attached.

View attachment 544622

I’m with you on the security bypass cable. It’s been installed for three years and now causing a problem? I doubt it too. I’ve had one permanently installed since 2019 and no issues. I do believe those connectors squeeze from the sides. You can reach out to MPGrimm on this forum as he is the resident electronics guru and most likely knows how to release those connectors.

 

[Lamarsh]

I do believe those connectors squeeze from the sides.

Thanks man. My guess was the security bypass cable was not the cause, but I wasn't about to completely disregard the idea.

I have tried to remove the cable carefully but have been unable to, and just don't want to force it. They don't look like they can squeeze from the sides, but I'll try it.

 

[Atcer2018]

Thanks man. My guess was the security bypass cable was not the cause, but I wasn't about to completely disregard the idea.

I have tried to remove the cable carefully but have been unable to, and just don't want to force it. They don't look like they can squeeze from the sides, but I'll try it.

This may help. It’s from the KaodTech installation instructions, #3 specifically.

 

[Lamarsh]

This may help. It’s from the KaodTech installation instructions, #3 specifically.

Thanks! Now that you sent that I do remember that from the instructions, and remember having a hard time doing it, but I sort of gave up and just decided to leave it on. Now that I really want to take it off to test to see if that's causing my issues I'll give it a better shot this evening. Thanks again! Glad you sent that, because I couldn't find the instructions that came with the KaodTech cord.

 

[Lamarsh]

I FIGURED IT OUT. It was a bad rear LED tailight and/or blind spot awareness sensor.
Two evenings ago I committed one last try into looking at wires, etc. Pulled my entire dash on the drivers side, inspected every wire. Everything looked fine. Decided to take one last attempt cruising around forums to see if I could find somebody with at least a similar issue in order to at least know what was causing it before taking it to a dealership, and found a guy on another forum that had THE EXACT same issue a year ago. EXACT SAME SYMTOMS (blind spot awareness unavailable message, blank/black infotainment screen, no AC, no front windows power, no backup cam). He tried a new battery, nothing. It ended up being a short in his drivers side tail light. (Here's the thread https://**************/community/threads/electronic-issues-radio-ac-and-front-power-windows.51474/).

Then a lightbulb went off in my head--every few months for the past few years I get a message on my cluster that says my right rear taillight is out, but it never was, I'd always check it and the taillight worked. The message always went away after a day, so I never cared. Anyways, I decided to disconnect that taillight to see if that solved my issue, and it did. I also noticed one of the 12 male connector pins on the taillight assembly was broken. At first a few glitches remained, but I pulled negative battery terminal and reset the truck and everything was fine the next day. I've now reconnected the taillight, and everything is still working, but I still think it will come back with this taillight and I'm going to have to replace it. It's almost $1,000 on Rock Auto, but I'm just happy I figured it out and got my AC working before this heat wave coming tomorrow.

Thanks for everybody's help. This just goes to show the value of these forums, and also how important really looking through forums for guys that have had the same issues in the past and how they resolved it.

 

[Atcer2018]

I FIGURED IT OUT. It was a bad rear LED tailight and/or blind spot awareness sensor.
Two evenings ago I committed one last try into looking at wires, etc. Pulled my entire dash on the drivers side, inspected every wire. Everything looked fine. Decided to take one last attempt cruising around forums to see if I could find somebody with at least a similar issue in order to at least know what was causing it before taking it to a dealership, and found a guy on another forum that had THE EXACT same issue a year ago. EXACT SAME SYMTOMS (blind spot awareness unavailable message, blank/black infotainment screen, no AC, no front windows power, no backup cam). He tried a new battery, nothing. It ended up being a short in his drivers side tail light. (Here's the thread https://**************/community/threads/electronic-issues-radio-ac-and-front-power-windows.51474/).

Then a lightbulb went off in my head--every few months for the past few years I get a message on my cluster that says my right rear taillight is out, but it never was, I'd always check it and the taillight worked. The message always went away after a day, so I never cared. Anyways, I decided to disconnect that taillight to see if that solved my issue, and it did. I also noticed one of the 12 male connector pins on the taillight assembly was broken. At first a few glitches remained, but I pulled negative battery terminal and reset the truck and everything was fine the next day. I've now reconnected the taillight, and everything is still working, but I still think it will come back with this taillight and I'm going to have to replace it. It's almost $1,000 on Rock Auto, but I'm just happy I figured it out and got my AC working before this heat wave coming tomorrow.

Thanks for everybody's help. This just goes to show the value of these forums, and also how important really looking through forums for guys that have had the same issues in the past and how they resolved it.

OUCH on the tail light price! Happy to hear you got it fixed and hopefully this helps others in the future.

 

[Hardracer]

That's pretty awesome that you found it(hope you found it)
What do you think would cause a pin to break?
But it sounds like your perseverance is paying off...keep at it and post up further happenings.

 

[Lamarsh]

What do you think would cause a pin to break?

The only time that taillight assembly was ever messed with / removed was when I had some body work done this past fall, so they either broke it then or it came that way from the factory. In any event, the strange taillight out message has been happening for years, so it was faulty prior to the body work I had done. It happened long before my warranty expired, but it was one of those things that never replicated itself often enough to get a dealer to cooperate. That seems to be their new thing when you have trouble with your truck.