L shoulder button not working BUT ZL is. HELP?

So I recently picked up a used N3ds xl off eBay. The only issue it has is that the Left trigger button is non responsive. I have tried to blow on it. I also tried replacing the ribbon cables with new ones and that did not work either. The ZL button works properly tho. If I turn the ribbon cable connection upside down and connect it shows as if it’s always pressed. So I’m assuming it works. Not sure where the problem is.