gauge issues
 

have a 94 silverado 2500 with the 6.5. have a strange issue with the cluster lights not working properly. when i turn the lights on the cluster does not illuminate but all the other lights (external, radio, 4x4, climate control) turn on and dim when the dimmer is used. the cluster stays dark and the high beam indicator comes on (turns off when high beams are turned on) and both turn signal indicators turn on (stay lit and start blinking when turn signals are turned on). all the gauges except for the tach and speedo go all the way to the maximum position (needles are pegged). when the lights arent on the cluster works properly. checked all grounds and all grounds are clean, complete, and ohm at 0.00. when i first got the truck the cluster lights would work properly on occasion. am not sure what the isue is. any suggestions? im out of ideas and am not wanting to tear the dash out to inspect all the wires yet. **did replace the light switch since i had a new one laying around. no change at all**