NoPistons -Mazda Rx7 & Rx8 Rotary Forum - Little heat when set on 'face'

'88 Convertible with 135K and owned from birth...

When heater is on 'face' - the air coming out is not very warm but when set on 'floor' its nice and hot down there. When set on 'both' - the floor is hot but face is hardly warm. Blower strength is fine. Its very strange in my opinion. Not sure if this is relevant but this past summer when A/C set on 'both' I got warm air on floor and cold on 'face'. When set to 'face' only....nice and cold. After driving a while the air on the floor does turn cold. Not being a mechanic I don't even know if there is something I can check easily to see if something about the air blending is not connected? Any advice would be very much appreciated.

Thanks in advance
Terri