So at this point all you know is that the backlight works.
It's time for you to disconnect everything and start again using the step-by-step procedure outlined below. I have been periodically posting this for years now, the last time was in June I think. You may already have seen it since that's my sketch in your original post.
=================================================================================
I guess it's time for me to re-introduce my generic step-by-step approach.
(1) If the module has a backlight then get it working properly. This involves only pins 15 and 16 on most LCD modules. Make sure to use a current limiting resistor if there is none on the LCD module.
(2) Get the power and contrast working properly. This involves only pins 1, 2, and 3 on most LCD modules. You should be able to just barely see blocks on one row of a two row display and on two rows of a four row display.
NOTE: The Arduino has not been used yet, except as a possible source for the power needed for the first two steps. Do not try to go any further until this is working. If you don't see the blocks then no amount of program code will help.
(3) Connect the LCD R/W pin (pin 5) to GND.
(4) Connect the six control and data wires between your LCD module and your Arduino. Make sure that your wiring matches the numbers in the descriptor (or vice versa).
//LiquidCrystal lcd(RS, E, D4, D5, D6, D7);
LiquidCrystal lcd( 7, 8, 9, 10, 11, 12); // put your pin numbers here
(5) Upload your sketch and it should work.
For troubleshooting a 'static' sketch, one that displays a simple message or two and then stops is recommended. All of your code should be in setup(), and loop() should be empty between the brackets.
#include <LiquidCrystal.h>
//LiquidCrystal lcd(RS, E, D4, D5, D6, D7);
LiquidCrystal lcd( 7, 8, 9, 10, 11, 12); // put your pin numbers here
void setup()
{
lcd.begin(16, 2); // put your LCD parameters here
lcd.print("hello, world!");
lcd.setCursor(0,1);
lcd.print("it works!");
}
void loop()
{
}
==============================================================================
Don