Hey guys, sorry if i've posted this in the wrong section!

My 2005 VZ Acclaim has a weird issue where i put the temperature to cold and it starts coming out of the vents then when i accelerate it quickly goes to the front demister.

Heater works fine from the vents. If its coming out of the front demister i put it to heat then quickly back to cool and it works for a couple of minutes before going back to the demister.

Has anyone encountered this problem before?

Thanks guys