HI :
I'm using the exactly the same IC driver this one right:
http://www.st.com/stonline/books/pdf/docs/1773.pdfhere are somethings you can check :
the sense pin is the PWM signal generated by the microconntroller but if you whant the motor to run at full speed connect it to 5v
connect one of the inputs to ground other one to 5v and enable also to 5v test it like that if it works then there is something
wrong with your signal
if on side of the h-bridge isn't working check the other side (maybe one side is broken or something)
and check how many amps your motor requires because if it's more than 2A but less then 4A then you can parallel the h-bridge so that both bridges control the same motor
if nothing else works then a take apart the whole circuit and re wire it .... if still you checked all this then it's almost safe to say the h-bridge is broken ...
(and PS : be-careful with it's pins they tend to break easily )
Regards
Jak24