1.8T Quattro various electrical issues

[roxya]

• One electric window does not operate (there's a click from inside the door after pressing the button, but no action)
• Coolant temp gauge is always too low (I do have an error code about coolant temp/thermostat though, so it's expected)
• Fuel gauge usually shows full or empty instead of the correct reading
• Most annoying one: indicator timing is extremely irregular, and often stops working after the first "click" (hazards are fine though)

Is there anything related here or is it just coincidence?

Thanks!