LCD 20x4 to arduino uno

Hi guys! So first of all i would like to say that i'm an arduino rookie! I bought my first arduino a couple of days ago together with a 20x4 LCD display( I've wired it up as the standard diagram you can find in here (, but can't seem to get the contrast adjust on the LCD to work. The back light is fine.

A can measure different voltage levels as i turn the pot on pin 3 and ground. I've checked that the pin 2 (Vd) gets 5V all the time. Any way to check if the contrast adjust is working?

At times like this a good, clear photo of your wiring is worth a thousand words! Try keep the image file size to a sensible limit too.


as written above(below) a photo of your "setup" was necessary.

But, if you want to found out by yourself, you can use the Samples and Tutorials (Examples,Playground) or, if you have an Android device, you can use this App:

You have a display that can operate over an extended temperature range. Typically these devices need a negative voltage between LCD pin 3 and GND unless the ambient temperature is very high.

To check this out you can use a 9V battery. Disconnect the end of the potentiometer that is currently going to GND and connect it to the negative side of the battery. Connect the positive side of the battery to GND. You should now be able to vary the voltage at LCD pin 3 from -9V to +5V.