Water damaged phone - home button not working

Customer came in with a water damaged phone. Took it apart and cleaned with 90% alcohol.

Phone now turns on fine after installing new screen (old screen was shot). But the home, power, and volume buttons don't work.

I've installed a new home button and it still is not working. I've ordered the rest of the buttons to re-install but am wondering what could be the problem with the home button? I would have thought a new home button would do the trick, but it didn't.

Any ideas?

Thank you,