RPi Zero + Grove RGB LCD Backlight - Shows no Text


I use a raspberry pi zero + Grove hat zero.
I followed the steps from the wiki: https://wiki.seeedstudio.com/Grove-LCD_RGB_Backlight/#play-with-raspberry-pi

The backlight works fine. But the LCD display doesn’t show any text.

Any hints?

The problem is: RPi uses 3v for its I2C bus and the LCD needs 5v. Ordered a 5v-3v level switch. This should solve the isse