Loss of class 2 data

[MyrtleBeachZR5]

Hey yall, my name is Chris. I have had an 03 zr5 for almost a year now and I've been having a common issue with seeming different causes.

I have the dreaded Christmas tree dash and loss of gauges on the class 2 serial data line. Others unaffected. Courtesy locks and automatic lights dont work either when data is down.

Using a bluetooth obd2 reader and my phone I noticed I lose connection when the gauges are down. When gauges work, everything else works fine. I'm thinking about doing the big 3 upgrade and adding redundant grounds at various points. I plan on putting in a new headunit as mine is about shot, I understand class 2 runs to the stock radio so there is one thing out of the equation already.

My security light comes on when the gauges dont work, and stays on solid until I disconnect the battery (occasionally it will go off on it's own too).

Thanks for any tips or help. I'm putting on a wynjammer and a few other mods in a week or two and lol have to get tuned obviously...I'm afraid the loss of class 2 data will prevent that. I've searched and can't find any resolutions or even wiring diagrams for the crew cabs although I did read about the front half of the crew cab being blazer wiring. Not sure if that's true or not

[LoneWolf04]

Just out of curiosity, any aftermarket items installed in the truck? Anything tied to the electrical system?

When you hook the ODB2 adapter up, try to access each module and see what codes you have.