Scored a mint climate control switch off eGay for $51. It showed up two days ago and I installed it yesterday. Now that I have got them working I have a question. There are two buttons on the top right. They look like selector switches for outside air/recirculate. However there is another slider switch in the dashboard above the little change compartment that has a similar symbol on it. When I move it side to side, it appears to cut the air flow to the vents on the end of the dash. Exactly what is this switch and what is it for? Also, am I right about the other two? I noticed one position makes the blower motor really crank.

BTW my car does not have A/C if that matters.