Intermittent Electrical Module issue

Ok so I have a 2019 Laramie Crew Cab 4x4 5.7L non etorc. She generally sits in the driveway during the week as I travel extensively for work. So, I only drive her occasionally on the weekends.

Here is what has happened so far.......

3 weeks back, Friday went out to dinner with the little woman to Chili's. Just after parking and getting out of the truck, unable to arm / disarm truck with remote. Replaced batter in remote seemed to fix issue.

2 days later, pulled into Sam's and the truck wouldn't turn off. Truck stayed in the MUX / On state. Messed with it for a bit and gave up, just locked the doors and went in to do what I needed. When I came out everything worked fine. After dropping of my buddy and his stuff on the drive home I hit a bump and the whole trucks electrical system seemed to reboot, Stuff went off and back on got all kinds of messages on the display, but she ran fine and got home. Well, this seemed similar to the battery failure back in March, so I grabbed my smart charger and hooked it up. Sure, enough it was a tad low, so I left it overnight. In the morning she started right up, ran fine all of the day but I noticed that on the volts gauge she seemed to be all over the place on each drive. First 14.5 then next drive 14.1, the next 13.9 I also started having issues with my electric steps not dropping with the door being open.

Couple of days later when back in town, I decided to pull the battery and get it check out. Went to Autozone and they didn't even look at it just gave me a new one. Ironically exactly 6 months to the day and time give or take a few minutes. Lol Well cleaned everything up and put in the new battery. Put the smart charger on it and let it sit overnight.

Next weekend I head out thinking everything was fixed now. Nope. I could drive somewhere and sometimes everything worked fine and others she wouldn't turn off or lock the doors, steps might come down, heck even the truck would stay running by itself if I tried to shut it down.

Ugh!!

Well, I did some searching on the net and came to the RF module on the back wall. So, I pulled the carpet panel and looked, actually pretty clean just a small bit of dust. No moisture or signs of moisture. However, I did notice that one of the wall vents does have a torn flap, so I have ordered a replacement. Ironically this is the vent directly above the antenna. So, I pulled both the antenna and the RF hub. Antenna is sealed with what looks like a vent, but I don't think it's open in anyway. As for the RF hub it has some dust on it, I popped open the cover and looked at the board under a light microscope and didn't see anything that was suspicion.

So, I'm back at square one.

Essentially several of the electronics systems stop working randomly for say 10 to 15 minutes then everything goes back to normal.

My plan now is to pull the headlight switch to access the CAN barrier strips, and measure voltage to see if I can locate one that is off when this issue arises. Is there a diagram or list that identifies which plug goes to which module?

Thanks for any help.

Maybe try hooking it to a code reader? That's where I'd start first before messing about deeper than you may need to.

Intermittent electrical issues are the worst. I was thinking maybe a loose ground somewhere. Good luck!

Brandon-w said:

Maybe try hooking it to a code reader? That's where I'd start first before messing about deeper than you may need to.

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I've used Alpha OBD, AppCar, HPTuners MVIC3, and had no codes, until just recent. I received a Lost BCM Communication code. a U something, I wrote it down at the house.

Have you solved your problem?

Kczaro said:

Have you solved your problem?

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looks like we'll never know...some posts are like a mystery book with the last pages torn out.

No, it's not solved. I quit for several weeks but recently just came back. I thought I might have accidentally fixed it with all the fiddling with different things, but that's not the case.

As before, I'll be driving along and all of the sudden everything resets / turns off and back on. But not everything works after this. Examples of the issues:

- Gauges recycle and red security light on the dash comes on stays on till I cycle the key.
- Go to park and can't turn truck off with push button. Have to sit and wait 5-10 minutes and everything resets again and then it works.
- Driving - resets and now I have no Turn signals, brake lights, front power windows, AC.
- Driving - Gauges turn of and come back on, but no indications such as fuel level <- just at empty.

I'm suspecting it's the BCM. I was trying to measure the CAN voltage on the bus bars but found out my multimeter was no good. lol

I did get a new multimeter, but now it doesn't want to co-operate with me lol.

I also pulled off my Gateway Module bypass and reconnected the gateway, since I read under some techniques for testing the CAN Bus that you need to test the voltage thru the Gateway. Not really understanding how they want you to test it that way. Through the OBDII plug or thru its connectors.