Fresh Air Vent/heater q's

[brentleedragon]

I have a couple questions,

On the passenger side by the floor, there is the vent door that when the truck is off or the ac/heater select is off, the vent door to let the fresh air in is closed (blocking any fresh air from getting in) as soon as I turn the truck on and put my selector on HI-LO/HEAT/DEFROST it falls down. Is this supposed to be down when the heater is on? I ask because when the truck is sitting at idle, the heat is strong and hot, but when I am driving it is like there is cold air getting in through that fresh air is diluting the heat making it more cool than hot? so is that door supposed to be open or shut when the HI-LO/HEAT/DEFROST is on?

my next question is

when I have the selector on Defrost it goes to defrost, when it is on heater it goes to the floor, and the only way to get it to the vents on the dash is by having it on HI-LO, is this normal or is there a problem?

I believe I have a vacuum problem as I hear a hissing sound from inside the dash when the truck is on and after I turn it off, that I am pretty sure shouldnt exist

 

[sicktight722]

lol, my bad, i didn't realize this was in the Gen 6 forum. I should pay more attn.

 

[brentleedragon]

Ah yes you're right I guess should put that info shouldnt I?

Its a 79 F-150 Regular Cab 2wd
302
c6

with factory AC and the "deluxe" heater as I believe it is called? because it has HI-LO

 

[Brian_B]

Gen 6 is 73-79 (I think). He is new here.

If you can...you should put your truck information in your signature. That way people won't need to ask next time.

As far as the newer trucks like that...I have no clue. Mine has a heater that is either floor or defrost (or turned off under the hood).

 

[brentleedragon]

Yeah I didnt really think about posting the info because it said 73-79 lol

 

[Mil1ion]

 

[brentleedragon]

Thanks Dennis, so mine is working right, maybe it is leaking somewhere in the dash. I looked today and I need to replace the foam on the doors because they're not there. What type of foam should I use? does it matter?

 

[Mil1ion]

It is a light density foam.

Check in the window/door sealing section of a Building material store like H/D.

 

[brentleedragon]

alright very cool. Also is there a heater valve on the truck? I see what might be one on one of the two hoses running into the truck's heater box, and I am thinking it might need replacing

 

[Mil1ion]