my heater isnt working properly?

hi all,i have a mondeo mk1 2.5 v6,and im having heater probs,

when i put theater fan switch to number 1,it blows hot air,but on 2,3 and 4,it blows cold air,

ive replaced the heater unit,but that one does nothing on speeds 1,2 and 3,and then blows cold air on 4,

is this the heater matrix?or just a duff replacement unit?

hope you can help,cus its freezing in my car!!!