It's just started getting really cold here in Central Indiana and (of course) I'm having trouble with the heater. At least I've NOTICED that I have an issue.

It seems the port that directs heat out the bottom of the HVAC box is not opening and when I am in "heater" mode, I hear the fan laboring and no air comes out anywhere.

If I put into DEFROST mode or dash-panel mode, I get hot air as expected.

My guess is that the actuator that moves the door to let air out the bottom is not working.

Can someone point me to where this item is under the dash so I can find it without spending an hour upside down under there?

Also, what is this thing called so that I can find a new one to order?

Thanks!!