Why is my backlight only working at a certain brightness?

I have a handed down Macbook Air Early 2014(A1466) that is showing some odd backlight problems.

Upon opening it up the first time the screen was dark, but I could still make out the screen contents with a flashlight. Some searches results yielded that this is a backlight issue. Shortly after that initial bootup I tried booting into recovery mode and the backlight started to flicker until it was fully illuminated, however after a restart the backlight was off again. I did a PRAM and SMC reset, which also did not help.

This initially led me to think that its possibly a bad screen cable causing the problem – I had ordered the proper screw set to open back lid as they aren’t available to buy at retailers in the area. In the meantime, I decided to do a ‘factory reset’ and reinstall the OS (doing all this through external monitor as that still worked).

It’s during this were it gets confusing for me – because during the actual install phase the backlight just simply turned itself back on, clear as day. Even when the screen went dark during the installation a few clicks would turn it back on. However, a restart simply made the backlight go off again, but this time I waited till it fully booted (with external still connected) and checked the display setting – turned off the automatic brightness and as I was switching between the External’s settings to the built-in, the backlight turned itself back on again!

Anyway, I was able to replicate this switching on of the backlight by tinkering with the display settings again, since restarting still did not help. This is also when I noticed that once I got the backlight to work (which would ony be on a low brightness setting) and I attempted to move it past approx. 70% of maximum brightness – it would cut the backlight out, so it won’t turn on during boot up and will not go past a certain point of brightness when I can get it to work.

What could be causing this?