No - that is not normal. The Fresh Air Vents in the Dash should not have air coming though them, when the selector lever is moved to "HEAT". They should have fresh air coming in only when "VENT" is selected. Fresh air comes in though the cowl - and there is a "flap" or "door" that opens/closes to control the fresh air flow. If you have cold air coming in - something is not allowing that door to close when it should - or the seals on that door are shot, or the cable that controls it may not be adjusted correctly. It may be time to remove the Blower Assy - clean and reseal the air flow control flaps/doors. FWIW, Carl B.