MacBook air 2012 late turns off

Hi, Got a MacBook air 2012 late, With light water damage..

With some problems, To turn it on you have to disconnect battery and then plug charge in and it turns on by it self ? maybe a keyboard problem ?

When on it turns off in around 30 seconds? and the backlight does not work.

The light on the charge did not come on when plugged in, There was a bit of corrosion on the io cable connector ! so changed cable with new! this fixed the problem with charger light..

Please help many thanks ..........