weird electrical issue?

[Roughy_]

Have a 2013 Chevy 1500. Has 103k miles on it. Had a weird incident where my radio would randomly shutoff while driving, then shortly thereafter have multiple light flash on the dash, which was followed by the truck downshifting by itself without decelerating (Limp mode I would assume). This would happen for about 10 seconds. Then everything would go back to normal. Then it would do it again maybe more or two more times. 

I'm posting this here because I'm not sure if it the BCM, ECM, etc. All help and suggestion are welcome.

Thanks 

[richard wysong]

sounds like bad ground or connection, without a wiring diagram I don't know where but I would start by checking the obvious, battery cables, wires from the under hood fuse box, body grounds. turn the radio up and start wiggling wires and see if you can get it to cut out. you may try an extra body ground from the engine or battery

Edited October 11, 2022 by richard wysong

[dsr611]

How old is the battery?  Have you had it checked?  When a battery starts to go dead in these vehicles with everything controlled by a computer, crazy things start happening.  I'd go get the battery load tested first

[Roughy_]

22 minutes ago, dsr611 said:

How old is the battery?  Have you had it checked?  When a battery starts to go dead in these vehicles with everything controlled by a computer, crazy things start happening.  I'd go get the battery load tested first

I had O Riley's check the battery and alternator. They both checked fine. I'm suspecting its one of the 7 modules that connect to the BCM. I just don't wanna go throwing money at replacing all 7 modules including the BCM itself. I'm gonna try calling a Chevy dealership and see if they can scan for any issues with the modules themselves.

[Roughy_]

1 hour ago, richard wysong said:

sounds like bad ground or connection, without a wiring diagram I don't know where but I would start by checking the obvious, battery cables, wires from the under hood fuse box, body grounds. turn the radio up and start wiggling wires and see if you can get it to cut out. you may try an extra body ground from the engine or battery

I'm suspecting that its one of the 7 modules that connect to the BCM that's shorting out, are just bad. I'm also suspecting that its the BCM itself as well. The Battery was checked by o Riley's and is good, so is the cables. I've also checked ground straps, which have all been tight. 

[Roughy_]

Update: 

[Roughy_]

Update: Had a Chevy dealer run a diagnosis.

When they checked the negative battery cable, it came back to 400v. The tech said It should be 2v.