screen is getting dark starting at left side

Ray Jackson this will depend on what model you have and how your screen looks. Post some images of what your screen shows with your question. Use this guide Adding images to an existing question for that.

It is possible that this is a CCFL/LED backlight issue, T-con board issue or LED driver issue. Again to be more specific we need more information from you. If you can, remove the back of your TV and take a look at all the boards and, board connectors and wiring. Make sure the wires are all still properly connected. Again, if you can post plenty of images.