Most likely it isn't a bulb - it may be a larger issue. The 2nd Generation Tacomas have LEDs instead of bulbs on the instrument cluster. The life span of these is much longer than a standard bulb. They are also MUCH harder to replace as they are soldered on to a circuit board behind the face of the cluster.
My advice - call the dealership and have them come pick it up, and give you a loaner car. This is not something that you want to tackle on your own. Besides, if it is under warranty they will pay for it, but if you screw it up you will pay for it.
Let us know how it goes.
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