Trying to fix Flapper Boxes, need help.

[TurboRuf]

In the three years I’ve owned my 85 930 I’ve never had a need to use the heat or defrost. The car is only driven on sunny warm days. To this date the ventilation control system still confuses me somewhat.

If I look under the car I can see that my rear Flapper Boxes are open. When I move the lower red lever on the dash, the flappers did not close. So I tried to move the other two levers just to make sure I wasn’t doing something wrong and still nothing.

Down by the emergency brake I only have the electronic adjustment switch for defrost.

So what controls the rear Flapper Boxes? Where should I start looking to troubleshoot this problem? The Flapper Boxes look like they are in great shape, so I’m sure it has to do with the cable system.

Any help/diagrams would be greatly appreciated.

[Tom F2]

The electronic switch by your e-brake controls the flaps, or at least it does on my car.

[LeeH]

Here's a good discussion on the topic:

How Do I Get Hot Air To Blow Through The Vents!!!

[TurboRuf]

Tom,
What year/type is your car? When you turn your switch by the ebrake do fans go on as well?

LeeH,
Good read, but it didn't go into a lot of detail about cars without the two red levers.

When I turn my switch by the ebrake, nothing happens. I’m going to have to check power to this device. Maybe the motor that controls the two cables is bad?

Thanks for the help guys.

[Tom F2]

My car is an '83 911SC, Euro delivery car. It has the automatic heat control, which was, I guess, standard in Germany. When the heat activates, the electric fan on the engine goes on. My car does not have booster fans in the footwell area of the passenger compartment, like your turbo. My car does not have any red levers in the area of the e-brake handle. The levers on the dash are just to control the fresh (cold) air from the inlet on the cowl, and to direct the cold or hot air to the footwells or defrost vents. It's a bizarre system, but it works okay. I would suggest that you read the owner's manual carefully. They really do explain it, it just takes a couple of tries before you'll believe them!

[LeeH]

It sounds like you have the automatic system. If you have the ignition on (but engine off) do you hear the servo motor running inside the conrol box when you turn the system on (ie dial 9 or defrost). You have to listen closely... or take off the rubber around the emergency brake and look inside with a flashlight... you should see the servo moving the rod that works the cables.

Does the blower come on in the engine compartment?

[TurboRuf]

Thanks guys... you have been a big help. I'll dig out the owner's manual tonight.

Lee, my blowers are in the footwell area. No, they do not turn on when I turn the large center switch. I will listen for the servo tonight when I get home.