I got a hold of a Samsung Chromebook 2 that has a huge issue with the built in keyboard not working properly. I get...

Typically if you did not hit the button at one point or another and the light just suddenly came on, It indicates that there is an issue with the transmission that isn't allowing it to switch gears beyond whatever the top, non overdrive gear is. It is basically a limp mode. Have you noticed the engine running at higher revolutions per minute (RPM) at highway speeds? If so, the issue is likely as I described. Assuming this is an Automatic transmission we are talking about I would check the easiest things first. Such as is there enough transmission fluid in the system. The way to check this is dependant on vehicle manufacturer. Pull your Transmission's dipstick and assuming it is a flat metal style, it will likely have proper instructions for checking the transmission fluid. Typically though, unless Honda or Hyundai, it's Start the engine, get the car warmed up and stop somewhere flat. With the engine running and the transmission in Park, get under the hood and check the transmission fluid the way you would...