heaters on mk1 cab

just a quick question, on the cab, the large square heating vents are they ment to blow hot or cold air. on mine i put heat up to window and its hot air but if open side vents its freezing cold air. !!!!!  does any body know?? :dontknow:

Outer dash vents are for fresh air only I am afraid.

thats what i thought, had mk1 years ago but couldnt mind. can this be modded to hot

i wouldnt bother mate, i find i have to turn em off to breathe lol

chris