corvette95

Looking for general leads in the right directions. All of sudden, all warning lights came on, air bag, stability, check engine etc. (167k miles truck - decent shape non oem radio) . Took to dealer, BCM, hatch and door lock control module, air bag module--most all modules etc pcm and cluster showing no communication. Replaced BCM, no change. I figure it is in the data connection circuit but where do I begin, I can afford to aswap all module then start checking wiring harness for what will probably one bad module or one bad ground etc. Some general educated info would be appreciated. Checked with Tech2.

Patsgarage

No communication with multiple modules at the same time sounds like either a ground or voltage problem. Get a wiring diagram and check (with a meter, not just visually) the grounds. Ring them out from the connectors to the grounding point. If the battery is getting weak this could also cause this, but my money is on the grounds.

That Bad Man

I also recommend checking for a bad ground.

I had an 09 Tahoe that was going crazy for about a week. Found out the problem was a bad ground with the battery. I wound up buying a lead cap for the battery terminals. Just that little bit of lead fixed the issue for me. (I replaced the OEM battery with a red Optima)
Good luck!

MVR 155

I would have initially said bad BCM or ground.... You replaced the BCM so now I would check the ground