Why won't my iPhone 3GS connect to wi-fi?

My iPhone 3GS got severe water damage (for over 12 hours), and I have spent weeks on it, completely disassembling the entire device, and using a toothbrush to spread isopropyl alcohol across the logic board. Today I finally managed to get it up and running (no small feat). Unfortunately, the wi-fi switch in settings is grayed out and cannot be toggled.

I've spent hours upon hours to get this back up and running, and haven't seen similar threads anywhere. Does anyone have an idea for a fix?

iPhone 3GS is running iOS 6.