Message text written by Jon Messier
>I have a 74 and the knob states "1 defrost / 2 car"
and when I pull it out (about an inch or so) it stops.
At the point it is set, the defroster is engaged. I
can feel the heat flowing up near the windshield,
however there is cold air blowing from the other set
of holes that go to the vents near the feet and the
dash board.
<
Jon,
The dash vents will always give you cold air. They source for the air to
the vents is down stream of the fan but before the heater matrix. Also,
there are trwo vents on each side; one in the dash and one just behind the
dash aimed at the feet. If you are trying to heat you need to close these
off by twisting the litle knob on each vent.
The facia mounted knob operates a flapper on the heater assembly just above
the transmission. When it is pulled out to the second position the flapper
allows air out of the heater box in the area above the transmission. This
air should be the same temperature as the defroster air. If not there may
be a leak around the heater matrix allowing cold air to slip by unheated.
The knob has a detent in the #1 and #2 position and you can feel it snap
into the #1 position. If you can't pull it past #1 then either the flapper
is obstructed or the detent assembly needs lubrication. (The detent
assembly is in the knob assembly in the facia. Try shooting some WD40 down
the shaft and work the knob in and out and see if it loosens up).
Good luck
Dave
|