m17 R3, back light isn't turning on

New here and was hoping to get some assistance. I am currently on deployment at sea so I can't hook my laptop up to the internet. But this last week my laptop back light quit working. I can see my screen very faintly and if I shine a flashlight on it I can see the screen is working and see my desktop. Additionally, if I hook it up to an external monitor it works perfectly fine. I have completely drained power and disconnected the battery to see if it would fix it to no avail. After I disconnected the battery I was able to get the back light to come on briefly after I tapped the back of the screen on the left side but that was only once and now it will again not turn on at all. The laptop has been taken care of and never dropped. I am a certified 2M tech both Micro and Miniature CCA and have a full range of ESD safe tools and an ESD safe desk at my disposal. But I know little about laptops. Any assistance would be helpful of where to start looking. I feel like its a loose connection but again I don't know enough. It should be noted I did try to update the laptop a week ago when I had a slow internet connection and the update didn't fully download so I removed the update back to what I originally had hoping that was the problem and it did not fix the issue. I then updated both the Nvidia driver and windows update to the most current version. Additionally I no longer have internet access for the laptop. Thank you all in advance for your help I truly appreciate it.