Ok, I have the exact same problem with my 03 GMC 2500hd.
The driver information and odometer all change language on me, from French to English to Spanish, over and over. It will then stop scrolling and be normal, except being in a different language. Sometimes I can change it back to English on my steering wheel buttons, not always.
This has been going on for about 6 or 7 years now. The dealer said I had a bad clock spring as the horn also did not work, so I had my usual diesel shop replace the clock spring for $400, it made no difference at all.
I went back to my dealer with the results and they said then I needed to replace my cluster for $1000...!
I drove the truck for several years putting up with the oddball info center, then decided to check with a truck recycling shop, they had a cluster from a same year duramax for $150, so I jumped on it.
It took me 15 minutes to swop out the cluster and presto, everything was good. Great, first time in years.
That lasted 2 weeks until I started it one morning and there it went again, changing language non stop...!
I am getting very frustrated with this, it's the only problem with the truck, which with 230000 miles on it runs like a champ.
My diesel shop are also frustrated, now they are saying that maybe it's the Body Control Module.
Anyone have any ideas on that? And can you even change that out?