Dimmer Rheostat Test
Remove dimmer rheostat. See INSTRUMENT CLUSTER TRIM PANEL SWITCHES under REMOVAL & INSTALLATION. Connect dimmer rheostat to battery with 40-watt test light. See Fig 1 . Turn rheostat knob to full right and full left positions. Brightness of bulb should change without flashing or flickering. If brightness does not change or does not change smoothly, replace dimmer rheostat.