Tampa 928s

The center vent switch is enabled when the vent control **** is all the way up. Looking at the schematic I see it is labeled as a micro switch central nozzle and is connected to the control head. Does this switch when closed tell the stepper motor to fully close to provide recirculated air, or does it provide another function?

GlenL

It controls a valve to have air sent to the center vent. Now why they did that and not just a flap behind the vent I don't know.

Alan

The function of the micro-switch varies by year.

However at no time did it have any effect on the recirculate mode - and indeed there is no stepper motor for this - all air distribution flaps are vacuum solenoid controlled. Only the temp mixing flaps are truly variably controlled.

For S4+ models when the center vent is manually fully shut the micro-switch on the vent causes the secondary mixing flap to stay in bypass (open) mode so cooler air (direct from the evaporator) will be directed to the door vents (if open).

Alan

Tampa 928s

Does the same air flow movement to the door outlet take place on an 86?

Alan

I believe it does - but anyway its a minimal effect - just creates a slight difference in temps between the door vents and the footwell & defroster vents (but not by very much). Its not controlling the flow at all - just the way the air is mixed to this outlet.

Flow control to the door outlets is manual only - otherwise its always on...

Alan

Tampa 928s

As always Thanks again Guy's and especially Alan, your the man!