A failing fuse can make an intermittent beep noise in the instrument cluster, as can the AC. With the fuse, a slight crack in the conductor can cause power to the instruments to 'cycle' at a rate that depends on the seriousness of the crack. Replace the fuse is the cure, if this is the noise source. If it doesn't do it when the AC is off, then a good tech can tell you the component in the AC that occasionally makes this prolonged noise.
2003 Firemist Red/grey leather SL 500
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1987 Smoke Silver/burgundy mbtex 300E Sportline (SOLD)
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