Does not switch to footwell vents. Air continues to blow out of AC vents unless fan is turned to Defrost, then all is directed to defrost vents.

 

Where is the blend door for the Heater Core/ Evaporator located. Could be that door not moving.

 

So if I understand correctly the following things are true:

- Heater Valve in engine bay is open with no vacuum applied

- Air is *never* coming out the footwell vents

If the heater valve is open, then water should be flowing through the heater core and this will apply heat to the climate system. I have an imperfect understanding of the system (someone else please chime in), but even if the ECU and/or temperature sensor was faulty causing the a/c to still run, heat would still be applied from the heater core (unless that is blocked up). Statement 2 above confuses me though... why is air never coming out the footwells?

In my car air always blows out the footwell vents. The only thing moving the bottom slider does is adjust whether or not the footwell air is hotter than the dash vent air.

Cheers,

- Will

 

The blend door is the two rotating blend "flaps" driven directly by electric servos. There are a few AC threads going so don't know/remember if it has been said here but switching ignition on but not starting you should hear those servos whirring when changing from full cold to full hot on the temperature wheel, and also when going the other way.