And to test backlight is working try

Code:
Main:
LCD_Backlight = 0
LCD_Data = "T"
gosub LCD_Write_: PAUSEUS 50
LCD_Data = "e" 
gosub LCD_Write_: PAUSEUS 50
LCD_Data = "s" 
gosub LCD_Write_: PAUSEUS 50 
LCD_Data = "t" 
gosub LCD_Write_: PAUSEUS 50 
pause 500
LCD_Backlight = 1
LCD_Data = "-" 
gosub LCD_Write_: PAUSEUS 50 
pause 500
goto main