TO GET THE A/C AND HEAT CONTROL BUTTONS AND DIFFERENT BLOWER SPEEDS TO WORK PROPERLY, YOU HAVE TO PRESS THE DOUBLE ARROW BUTTON NEXT TO THE DEFROST BUTTON FIRST, AND THEN ALL OTHER BUTTONS FUNCTION NORMALLY.

I KNOW OF FOUR OTHER 1983 300SD'S WITH THE SAME PROBLEM AND REPLACING THE AUTO TEMP CONROL UNIT(WHEEL AND BUTTONS) DOES NOT SOLVE THE PROBLEM.

COULT IT BE THE BLOWER RELAY?

BILL

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Bill