I had the same problem with my 91 EGT. You may be in for a bit of a shock when you remove the instrument cluster. When I removed mine I had a melted mass of wires behind it. Apparently something had short curcuited it and caused all the bulbs to blow. I spliced in good pieces of wire to replace the damaged sections, replaced the bulbs, and put it back together. Its been four and 1/2 months now and I still haven´t had a problem with it. Yours may not be as bad but I´m willing to bet it is the bulbs.