Have you checked the fuse? Looks like fuse #7 (counting from L-R) controls the speedometer, not sure about the tachometer.
Whenever there is an electrical item that is acting up (or not working...), it's a good thing to check all ground connections.
Since you tell us the odometer isn't working I'd suggest checking for a loose/broken cable. I believe it attaches to the left rear of the transmission then goes to an sending unit to get converted into electrical signals (for the speedo). The tach gets its input signal from the coil.