I guess the bulb will have burnt out.
(Before attempting any electrical dismantling it is advisable to disconnect the battery negative terminal.)
First you'll need to remove the instrument panel, so fully lower the adjustable steering column to improve access, then starting at the bottom of the shroud carefully unclip it and remove it from the fascia. Slacken and remove the instrument panel retaining screw. Remove the instrument panel assembly from the fascia, disconnecting the wiring connectors as they become accessible.
Twist the relevant bulbholder anti-clockwise and remove it from the rear of the instrument panel. All bulbs are integral with their holders. Ensure the new bulb is of the correct type and rating and then securely fit the holder to the rear of the instrument panel. Refit the instrument panel by reconnecting the wiring connectors to it, clip the panel back into position in the fascia. Refit the securing screw, tightening it securely. Clip the shroud back onto the fascia. Reconnect the battery if you disconnected it, and check the operation of the panel warning lights to ensure they are functioning correctly.
Good luck, and let us know how you get on!
ChicksFan
July 2011