All of a sudden when I switch on the Ignition the HVAC display goes from blank to displaying all of the possible indications in the display. Does anyone have an idea of what is going on? Thanks in advance!

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1984 300CD (sold)
1973 220DPK 4 spd (died)
1978 350SL 4 spd gray market
2003 SLK32 AMG
1988 300CE (sold)
1997 E420 (Totaled)
1998 E320 Wagon