Ok, I've come to a conclusion, but am looking for suggestions on the fix. When the car is turned off, the fresh air vent flap is closed, as indicated in above post by Jax543210. When the car is restarted after more than a 15 minute delay, the actuator that controls the fresh air flap should be trying to open it, but on my car it is trying to close a flap that is already closed! I determined this by taking the actuator out of position and observing the shaft turn when the car starts. It turns the opposite way it would need to open the flap. So the cheap plastic gears that connect the shaft to the flap are basically trying to turn the shaft that has no more room to turn. The flaps can actually be seen by removing the cabin filter cover and the filter.
All the plastic gears on my Z are intact, none of them are broken and the shafts to the flaps are all good as far as I can see. The actuator works fine after the car is started. When I change from fresh air to recirculate, the fresh air flap is closed and both recirc. flaps open as they should. When the blower is turned on, the fresh air flap opens automatically, as it should, and closes when blower is shut off. The pictures show the actuator, the white plastic parts are the linkage that connects the three flaps that it controls. In the top photo you can see the opening(bottom of photo) where the cabin filter goes and if you look closely you can see the bottom flap.
I guess the next step is to replace the actuator, $104 at the dealer. Anyone have any ideas on why this actuator is trying to close a flap that is already closed? It is a two way motor, but the motor seems to be turning the wrong way, but only at startup. The rest of the time it works as it should.
Last edited by Jstic; 09-14-2012 at 06:06 PM.