Problem with vents in 96 Regal

[maurycy]

Hi,

I have 96 Regal Custom 4dr with dual zone climate control. For a number of months now I have a problem with vents. While driving with climate control set to VENT, the air will start blowing down by the floor (as in HTR setting) and then change back to VENT. Recently I noticed also, that when the DUAL button is off, the passenger vent by the floor blows hot air while other vents are blowing cold air. I have to switch to DUAL mode for the bottom vent to blow cold air.

What could it be? Any on-line instructions with pictures that will help me fix whatever needs to be fixed?

Thanks,
Alex