SIL still not working after HDD cable swap

Hi,

Recently I changed the hard drive cable in my mid 2010 15" MBP (2.66GHz i7) after breaking it. I bought it from iFixit and it included a replacement SIL assembly. After replacing the part the cable works (hard drives boot when installed internally) but the SIL still doesn't work. I've reset the PRAM and SMC.

Does anyone have any ideas?

Thanks in advance