flaper down in the pass side floor board???
Closed? like with the flap verticle? Up against the grill that you can see from the pass seat???
That knob is two stage - halfway open and it allows some air in to blow past the heater core - leaving through the vent closer to the driver (with a separate knob for "Temp"). All the way open and it fully allows air in through the cowl through that opening with the flapper. So much air that it kinda overwhelms the heater core and the air isn't so hot.
Thanks, Its been out all summer because I have been to lazy to put it back in so far. I just need grind the tacks off and reposition it the slap it back in before it turns cold. If the summer here in ga is any indicator of what kind of winter we will have it should be very cold.
I realize that this an old post..
In the process of refurbishing heater box in a 1983 scrambler due to leaking heater core, the amount of information in this forum on this subject is amazing. While putting cables back in, thinking that I had hooked them up parallel to the earths surface but couldn't get it to open fresh air intake vents. LMAO... who knew the knob would pull out till it hit the back glass.. problem solved. Thank you Walkerhound..