Arduino stops working when I2C access is needed

Hello everyone,

At first, this is my first post here, and I’m german as you may notice :smiley:

My problem:
Im trying to hook an I2C LCD (4x16 letters) to my Uno since yesterday. I connected the SDA and SCL to Analog ports 4 and 5.
But everytime I insert something like lcd.print(); in my sketch, the Arduino is not doing anything… I can’t even let get an onboard LED to light up. When I remove the lcd. parts, everything works fine.

Here’s my code, just in case I made a mistake:

#include <Wire.h>
#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27,16,4);
void setup() {

I hope my english is not that bad, and you got my problem…

Thanks for any help

Please only post whole sketches. In this case it might only miss a a empty loop() but it just makes it harder for us to test it.

Second, when using non standard please provide a link to it.

Thanks for using code tags though ;)

And the thing I notice, most libraries use some sort of begin() or init() function that needs to be called before you can actually use it. Because you didn't provide a link I can't check ;)

Did you connect gnd between arduino and lcd? Did you supply power to the lcd?