Should the I/O board be replaced?

I have a base model 1.7GHz Core i5 13" MacBook Air and about 4 years ago it suffered some liquid damage. Finally this month when I got the tools I opened it up, cleaning every component of the logic board and the I/O board with 91% isopropyl alcohol. When I checked out the I/O board, I realized there was more corrosion on there than the logic board. In fact, I don't think I found any corrosion on the Logic board. I only found stains on the logic board. (which I cleaned up carefully with a toothbrush)

Do you think there would be a problem with the I/O board, like the onewire circuit? Before I cleaned it, it would blink from a bright green to a dim green light at a slower pace. Now it's not lighting up at all. Well, when I plugged it in after I put the MacBook back together, A showed a bright orange light for less than half a second, and then it shut off.

My guess is the I/O board is fried. There might be something wrong with the logic board, but at this point I am kind of doubting that.