Help Needed in lcd JHD 162A interfacing with arduino2560

Hi Friends.. when i connect my JHD 162A lcd with arduino2560 i just want to test contrast but it not working i connect pot with pin 3 and also use led to cnfirm thats the pot is working. pot work good but contrast not changed :disappointed_relieved:

any suggestion??

use 10k or heigher pot it will work :grin: