Chosen Solution
Liquid damage. Cleaned with 99% isopropyl. I think I have narrowed down the possible problem to the chip shown in the red box in the pictures. I am wondering if it is possible to fix this logic board as the chip appears to have “rusted” connections.
Liquid damage is always tough to fix as you often have multiple issues that you need to work out. I would recommend trying to find someone local who has the skills and tools to fix your logic board. As you can see referencing the MacBook Air 13" Early 2015 Teardown which is the same basic board as your system you can see some of the damaged/missing components you’ll need to source. I’ve flipped the image around so you can reference it to your pictures correctly. The light Blue chip is the SMC chip which is chip you have focused around.
So then the next question is will it be cheaper than just replacing? iFixit is currently out of stock on the 1.8 GHz version of the board. Here’s an alternate source from TheBookYard in the UK, they also have the premium 2.2 GHz version as well. MacBook Air 13" Logic Board, 1.8GHz i5, 8GB (2017) P/N 661-08140 $401 USDMacBook Air 13" Logic Board, 2.2GHz i7, 8GB (15/17) P/N 661-02394 $470 USD
