toms73novass

I have a new to me 75 911, that has backdated heat exchanger setup (so no blower fan in engine bay).
The levers between the seats work properly, down no heat, up heat.
The levers on the dash. Red lower lever left heat at feet, right heat at windshield.

Is there a way to boost defrost heat with the blower in the trunk? When I move upper lever to the right it blows cold air even with the levers between the seats up. My understanding is the it is pulling air in from intake at the windshield and blowing that air inside, rather than the heated air from the back.
When I have the blower on and red lever to the left I get blown hot air on my feet...but it does not feel warm when to the right.

Am I doing something wrong?

Uwon

You have an issue with the defrost cables all right. Misaligned, loose or slipping connectors or missing outside sleeve clips.
With respect to getting some residual heat on the driver’s side when the red lever is off to the left, that is quite usual. It’s even mentioned in my owner’s manual and the suggestion is to turn off the side vent.
By the way, I also have the engine bay fan delete. Still lots of heat.
Hope this helps.

theiceman

i would say your flaps arent moving , you can take off the cardboard shield in the front and watch them while someone moves levers. .

toms73novass

My controls only have 3 levers:
According to the manual upper lever controls outside air left is closed middle is open to right is fan assisted.
Middle is direction of outside air left is feet up is windshield
Lower is heat direction left is feet right is windshield

So from what have read there is no "boost" to the defrost of the windshield it is just relying on flow from the engine fan to push warm air to the windshield. Because right on the controls it says move upper levers left and lower lever right for max defrost.

To me coming from chevy corvairs which are air cooled it is just odd that the blower in the trunk is not used to help move the heated air.......

theiceman

pretty much the same , just top one is split

middle one left lower one right . its the lower one that is giving you issues i think .

toms73novass

Thanks, will investigate.

Spyerx

My levers work fine, including the blower. My max defrost setting includes this kept in glove box:

toms73novass

Ok checked things out and I am getting warm air out of defroster, Just different animal. Thanks.

I think the microfibers would be a good addition.

theiceman

lol

i just rev it a bit, but if i have the settings wrong, my shoes melt.