Arduino uno and 1602A I2C not working I'm a newbie in engineering.

I bought this with arduino learning kit.

It's simply not working.

There are several possible problems:


The display is not working due to a hardware problem. It could need to be repaired or soldered better.
The library that I chose could be buggy (software problem)


How can I check this? Thanks!

PS Build-in led is blinking as expected.

Here is the code:

#include &lt;Wire.h&gt;
#include &lt;LiquidCrystal_I2C.h&gt;

LiquidCrystal_I2C lcd(0x27, 16, 2);

void setup()
{
  lcd.init();
  lcd.begin(8,2);

  pinMode(LED_BUILTIN, OUTPUT);
}


void loop()
{
  digitalWrite(LED_BUILTIN, HIGH);
  lcd.setCursor(0, 0);
  lcd.print("TEST");
  delay(1000);
  digitalWrite(LED_BUILTIN, LOW);
  lcd.setCursor(0, 0);
  lcd.print("   ");
  delay(1000);
}
Try with this address 0x3F or 0x27 

#include &lt;LiquidCrystal_I2C.h&gt;
LiquidCrystal_I2C lcd(0x3F, 2, 1, 0, 4, 5, 6, 7, 3, POSITIVE); // or 0x27
void setup() {
lcd.begin(16, 2);
}
void loop()
{
  digitalWrite(LED_BUILTIN, HIGH);
  lcd.setCursor(0, 0);
  lcd.print("TEST");
  delay(1000);
  digitalWrite(LED_BUILTIN, LOW);
  lcd.setCursor(0, 0);
  lcd.print("   ");
  delay(1000);
}