auto printing when cell is updated

Hi all

Can someone please give me a hand with this 

i'm trying to automatically print label when the cell is updated ( puling data from different workbook )

 so when i enter slp then s/n it should print it out but for some reason  it doesn't 

it's printing out if i type in the s/n filed  but not when its pulls data

i added file if someone would take a look i would appreciate