edgarcia737

I'm trying to understand how my ventilation control panel works. I have a 1977 Carrera 3. The Owners Manual is in German. I took my wife for a Sunday ride and she froze her butt off because I couldn't keep the outside air out. It wasn't that bad but I couldn't explain the ventilation controls to her.


Concerning the top two levers. I know the one on the right controls the forward fan motor. But what does the left one do? Fresh air/ Recir?

Regarding the bottom two levers. What do they control? what does the "down" triangle on the left side mean and the "up" triangle on the right?

Please but laugh too hard. I know it's a silly question. I started to use google translate but it's taking forever.

Ed Garcia
1977 Carrera 3

RL911

Pretty sure this has been posted on here before, it's not my diagram and its for an 86-89, but maybe it will offer some help...

Amber Gramps

I always had the opposite problem early on.

Check your flapper boxes....

rusnak

(I think) the '77 should have two floor heater levers between the seats. This allows both sides to be heated separately. The dashboard levers merely control the distribution. So if you slide the red dashboard lever to the right, it will direct hot air toward the windshield. If you slide the same lever to the left, it will direct more air toward the floor. Same for the middle lever, except it directs outside air either up or down.

If no hot air is entering the car, then you should check your heater duct hoses and the heater valves that direct hot air from the heat exchangers into the car. There should be two, on on either side of the car, underneath next to the exhaust.

Windshield defrost would be fresh air lever directing air down, hot air lever directing air up. If you keep the two levers together, then you will mix hot and cold air.

edgarcia737

Thanks guys. It all helps.

No A/C installed and this car has the rotary dial between the seats which controls the amount of heat entering the car. So I need to move the red lever (bottom one) to the left for warm air to be directed to our feet.

So with the upper left lever control to the far left, that closes the fresh air inlet?

rusnak

Ed,

Not exactly. The rotary dial that you mention only controls the tangential blowers in the footwells, unless you have the auto heat option. If you have manual heat, then the rotary dial moves air only and does not control the amount of hot air. You must open the heater valves (flapper boxes) in order to get heat.

The fresh air blower speeds up the entry of fresh air into the cabin. As long as the car is moving, you will get passive ventialation due to the fresh air scoop on the hood, and the air exits on the back of the roof.

I know this all sounds complicated, but it's not really. It's just complicated to explain.

duncan1437

it's a small world. i was up last night after midnight googling "porsche 911 sc heater explanation'.

you might find these interesting:

http://www.cutesphere.com/data/cars/..._930/index.php

http://www.dietersmotorsports.com/te...911_heater.htm

the main message/warning i picked up is.....don't pull the manual lever on the automatic rotary heat adjuster between the seats. it can damage the automatic heater adjuster. the manual lever should be used only if the automatic heat adjuster has failed, and is activated by loosening the release screw on the lever.

edgarcia737

Well again I appreciate the info. It's all good.

I'm currently on a business trip. so I cant wait to get home and show my wife I know what I'm doing ;-)

Ed Garcia
1977 Carrera 3.0

Daniel Dudley

Good luck with that !