I searched through this thread along with the entire forum prior to posting. I'm not ignorant, just simply asking for a little guidance. I wasn't finding any helpful posts walking through the forscan aspect of the process and you're posts still don't specifically help...
Save module info from 2024, remove 2024 controls, update 2021 controls with 2024 module info?
I want to see if I can make a whole post based on quoted information below that answers your problems.
I found a used one on eBay. It ended up being completely plug and play. No rewiring, no Forscan needed. Just have to take a bunch of interior trims pieces off, which was easier than I figured it would have been. The whole process took probably a half hour.
and mine again...Finally got around to doing this. Found out a couple of things in the process. I think a few people are getting lucky with an ebay unit from a salvage vehicle that is already programmed correctly and is plug and play. Most of the ebay units are either not programmed at all or the programming is not correct for our trucks. On these units, the codes for the HVAC module will have to be written, but your existing as built codes will work. You do not need to get codes from a 2021 VIN. Just use Forscan to write the codes saved from your original configuration, turn the truck off, and restart. Also pay attention that there are 2 parts of the the HVAC code to write to the new module. I overlooked the second one on my first try. After I figured that out, everything worked great.
I installed mine this morning, and after some frustration I realized I was just an idiot and the truck needs to be running for the heated and cooled seats, along with the heated steering wheel button to work.
After flashing information from a 2021 truck, and then going back to mine, only to start the truck to go for a drive and hit the button...
Everything works with my original ADB data.
Once I stopped being a **** and yanked off the trim piece on the dashboard, it was a few bolts out, a few bolts in, and then shoving it all back together. I'd say going slow and getting a headlamp and being all prissy about everything, under 45 minutes. That includes restoring my factory file to the new module through FORScan and all. Absolutely well worth it for the little digits in my eyes.
So, remove your unit. Install new unit. Use FORScan to program your stock values into the HVAC module you installed. Need more tech info? Again, get familiar with FORScan and that will solve your issue, man. Load up FORScan. Need an adapter? If so, good God please read up on how it even works. You probably have an Apple laptop, too? I mean dude, come on man. Load up FORScan before you swap anything hardware related. Save your factory HVAC files from FORScan to somewhere on your computer. Do the hardware swap. Load up FORScan. Load your factory HVAC values into the new HVAC unit that you just physically swapped.
If you still don't know, don't do it.