LCD 16x2 Arduino Mega problem

me too i thought should be 1,2,...15,16. but it's different
from 14,13,...2,1,15,16.
It's on the datasheet and also on the board written. Just if it's a mistake that I don't thinks so.
What is your opinion?

MAS3:
I'm sorry, but it is not wired correctly.
We all were looking at the pot and it's wiring.
But your last photo shows something that wasn't directly visible to us, you have 2 more solderpads left.
These pads are at the right hand side of your display.
If pin numbering would be standard, these pins would be pins 0 and -1 and that makes no sense at all.

Are you sure your pin number 1 is number 1 and not number 14 ?
I suspect it really is number 14 and in that case all bets are off.
Please show a clear photo from top and bottom of your display module, showing the connection pins without anything connected to it.
This will very likely give us some clue as to where pin 1 is.

Edit:

Your PDF document can't be opened (here).
Well after searching a lot, i found that this is an oddball LCD with a non standard 16 pin connector.
This connector starts with 16, 15, 1, 2, 3, and so on FROM RIGHT TO LEFT.

So back to start.. :frowning: