Just to confirm what Peter said, it is a bulb, (or it was I mine, I replaced it today). You can check that the display itself is working by shining a bright torch on it-you'll see the figures are still there. On my '99 Astra 1.6, you lift off the top steering column cover, (black plastic with sping clip fit), this exposes the lower two screws of the instrument surround, undo these and then the top two above the cluster. (You'll need a six pointed T20 type screwdiver bit if it's like mine). You then remove the surround by lifting it out and towards the door, keeping it behind the steering wheel. Then move the white clip at the top of the clocks upwards and then to the left to release the electrical multi connector. Pull the cluster slightly forward to release and then push one corner in, to angle the cluster out through the steering wheel. You'll see the bulb in the back now, turn the holder through 90 degrees to release. On mine the bulb was integral to the holder and the whole thing was replaced, (£1.46). Hope this helps!
Simon, April 2010
