Try replacing the rheostat brightness control. Had same problem and though the dimmer was working, it didn't allow enough voltage through to light bulbs.Make sure that you're getting a full 12V out of the dimmer when it is wide open. Be careful not to short out anything when doing it! I had the same problem and this solved it. The other obvious culprit could be the ground connection which is usually supplied to the whole instrument cluster via a wire through the multi-pin connector, or separately. In American cars they usually are a brown wire to ground...can't say if yours is the same though. Also,check continuity from your ground wire to the surface ground of the cluster...if no continuity you know its the ground. Then try tightening all the outer nuts holding the cluster together. Good luck, Jeff