replaced home button but now goes to voice control

I recently soaked my Iphone 4 in a kayaking spill (forgot to place it in a water proof case). I dried my iphone out and everything worked fine except my home button. I purchased a new home button from ifixit.com and followed the step by step instructions from ifixit.com and installed the new button.

This worked great for 1 week and now the home button activates the voice control when pushed instead of closing the current application. I reformatted my iphone to factory settings and uploaded my data from backup hoping this would solve the problem but it does not. Pushing the home button activates the voice control.

Has anyone encountered this problem and worked it through to a solution?

Thanks for all input,

Al