I remember that some people would seal their front vent so there wouldn't be any leakage.. that they would put something in front of the vent on the outside to block the air... and I know that Terry sales a front heater shut off valve... and I removed the central plastic vent cover on the inside by the AT shifter... and have indeed noticed that there is hot air coming through this vent area with my heater shut off... (Im in California and it is hot... ) though I'm not clear if this hot air is coming from my heater or if it is coming from the outside... and if you seal the front vent from the outside.. would you still be able to defrost you windows.. (and if not then could you just defrost with a small fan like that sold by Westmarine and powered by D batteries...)... 

So Im wondering should I just disconnect the front heater and get rid of it and all the piping... (plan on getting propex..).. and seal the front vent from the outside... I'm tired of getting hot while driving...