Welcome! I am an experienced electronics field technician and your satisfaction is my top priority. We are now connected together on this convenient website.
If you got a Vizio remote (not a universal), then there is no need to sync it to the tv. The remotes for this tv do not require syncing. There is a way to use a digital camera to test the output of any remote, just point the tip of the remote into the camera and watch the camera screen as you press buttons on the remote. You should see a flickering coming from the tip of the remote in the camera screen.
If the remote is sending the signals, then it is likely that the sensor inside the tv is bad. That will mean replacing the sensor inside the tv. If that is something you want to attempt then reply back here and I can assist you further.
If you are unable or unwilling to perform any of these procedures then a repair shop should be consulted. A shop charges $125 to come diagnose the problem and hand you an estimate. Then possibly another $175 in parts and labor. So the total can be almost $300.
I'm sorry for the bad news. Remember that I am here to help you. Please reply back if you need clarification on any of the above.
Regardless of what you decide to do next, please take a moment to click the 3 to 5 STARS rating at the top of the page. Keep in mind that I have donated my invaluable time and expertise helping you rather than other paying customers.
Rating now does NOT close the question or prevent us from continuing our conversation here. My livelihood truly does depend on your positive rating.
Clicking the "bad/poor" rating does NOT do anything to fix your issue, nor does it issue you a refund.