I replaced the LCD on my 3D printer and tried using the old one with my Arduino Uno. The LCD is a 20x4 character one with 16 pins. It is on a shield with 5 more buttons and the necessary resistors. I followed the PCB traces and wired it to the Arduino like this.
After uploading a LiquidCrystal example sketch and changing the display to 20x4 the LCD displays nothing or weird characters. It would be nice if somebody helped me.