Same thing happened to me last Thursday while driving in Illinois - left side of the display went blank. No speedometer or gas gauge. Took it to a local dealer who diagnosed the problem but said the part was not available in the Chicago area. Brought it to our local dealer today who said it needed a new "combination plate", apparently a circuit board. Will take several days to get the part. Toyota will be providing a rental car. I think I'm going to buy the extended warranty.
Same exact thing happened to me last week. It came on the next day. Please post again if you get it repaired or have more problems.
I have a 2009, the instrument lights go out when I turn the head lights on. With the headlights off everything works fine. Just had the windshield replaced, could they have done something to mess it up?
Check the slider wheel to the left of the steering wheel that controls the dash brightness. It only works when the headlights are on. It's possible it's been turned off or down.