Hello there, I have a story for You, so grab some popcorn and enjoy it, then please answer my questions if You have any ideas on fixing that.

So, back in the spring, on a sunny day I decided to clean my windshield from the inside. Grabbed some glass cleaner spray, a squeegee and some towels, and started cleaning. When I used the squeegee to take off excess cleaner, some of the liquid landed on the dashboard and ran down between the top glovebox and the main dashboard panel, probably ran on the outside of the lower glovebox and down to the GEM. I was like "meh, it's mostly alcohol and distilled water, what's it gonna do?" Nothing happened until I ended the procedure of cleaning the glass, but then the wipers started to run, the IC started to beep and I couldn't do anything about it, as there was no key in the ignition switch (it was actually in my pocket) and the car didn't start when I tried. But after several minutes of beeping and wiping everything went back to normal. At least it looked like that. When the atumn came, I noticed that I can't switch on the heated rear window, so I checked the heating lines on the glass. In several places the lines were covered in patine, and It looked like it was caused by the previous owner who applied the foil on the inside to darken the glass, and probably he did it with some water. So I thought about changing the glass. But it was too expensive, so I bought used trunk lid with working and tested heating. After connecting the "new" lid to the bundle without installing it, the heating didn't work as well. So I tested the switch, by initiating GEM test. The test worked, so the switch is OK. Then I removed the GEM and had a look at it. Nothing special, two patined connections, cleaned the pins, cleaned corresponding plug, got it back and plugged up - no change.

Do I really have to replace the GEM, or is there a way to fix it DIY way? There is really nothing about this on the internet, so I'm asking You.
Regards

Can't edit the post, so I'll reply to myself lol

The cure was replacing the GEM module. Now everything works flawlessly. Just a quick swap of the module and assigning the remote with new GEM, under 30mins of work.