Here's a rough guide how to remove and repair your instrument panel. My speedometer and odometer started to behave randomly. Sometimes the odometer stopped running, only to start start working again after a while, or the speedo would suddenly stick to 80km/h. Tapping the instrument panel would help, so I figured it must be a bad connection.

First remove your instrument panel. Lower your steering wheel to lowest possible position, and remove the upper plastic cover. You can then remove the 4 allen key screws that hold the instrument panel frame. Now the instrument panel can be pulled out and up or left from behind the steering wheel. Disconnect the three connectors.

Once you get the panel out, remove the five phillips screws and six M3 size nuts (5.5mm socket). Carefully remove the black cover, and pull the panel out.

Carefully check for cracks in the joints - 2 out of 4 of the big ones were damaged in my speedo circuit board. (See pics). Re-solder the joints, connect the cables and test before reassembly. You can replace any broken bulbs as well while you have the panel removed.