On my 1985D/T there is no air from the center outlets. As I understand this
from the owners manual there is a switch over that opens the flapper when
the system calls for air and closed it when the system calls for heat. My
question where (physical) is that switch over located? It must be
electrical that sends current to open the vacuum valve of the flapper.
1985 300 D/T 303000 one owner miles.
1978 450 SL Odometer shows 130000 miles title shows two previous owners
1966 Ranchero 102000 one owner miles
Outgoing mail is certified Virus Free.
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my problem is the reverse
on my 84SD i looked behind the console scratched my head.
pulled the tunnel off and opened the 2 flapper doors and got heat at the
floor and turned the dash vents off by the slides.
the case, minus a few cans!
On the 123 body, it is very very rare to lose the center vent switchover valve.
9 times out of 10, the vacuum element is ripped.
The other 1 out of 10 is the plastic pin broke that attaches the element arm to
the center vent
The center vent element sits on top of the heater housing right under the middle
of the dash. The
hot sun cooks the area every day the car sits outside.....
This situation is the default setting when there is not enough vacuum to
operate the vacuum elements which control where the air comes out. You might
have a leak. follow the vacuum line from the top of the vacuum pump on the
front of the engine. Remove the left two lines and block the vacuum fitting
with two golf tees. This experiment should do the trick and provide smoother
shifting and smoother running engine. If it doesn't work, replace the vacuum
hose coming off the vacuum pump with a piece of new vacuum hose and check
all the plastic vacuum lines to make sure they are sealed at each end. You
may need to replace the vacuum elements. Get a vacuum gauge for about $20 at
Sears and remove the glove box lining. There is usually a vacuum bar with
lines going to it. You can plug the vacuum gauge hose into each and see if
it reads any vacuum. If some do, and some don't, you'll need to remove the
dashboard to replace the vacuum elements. They are availble from Rusty
(buymbparts.com) at 800-741-5252. P.
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