Possible a loose connection
Possible the light bulbs are gone
Possible you have a mechanical tech problem
Contact Stevechumo. He might able to help. He is my Cluster Guru.
Does the tach not light up or does the needle not move from zero? If it doesn't move try flicking the clear cover a few times. If it doesn't light up youi have to replace the needles or go to Lexus and order a new speedo assy which is $500+