Heating system
 

I have just bought a 1993 impreza import, the heater inside the car works great but when you turn temperature to cold it doesnt change to cold, any ideas, switch seems fine

Heater is a full flow item (no valve controlling water) so the hot/cold is controlled by flaps mixing hot and cold air.
Depending upon the model these flaps are electrically controlled (solenoids) or mechanically controlled(wire rods).

Sounds as if the mixer flap may not be working / become disconnected.

Thanks,any idea were the flap is in the car?I think mine is electrically controlled,is there a fuse for it

What model impreza is it??
Update: - found on another thread WRX which comes with auto HVAC.

Heaterbox - flaps marked in yellow; some of the solenoids/motors marked in red.
http://clarkdh.net23.net/NTL/Heaterbox.PNG

As to fuses it could be a number involved, so best to check them all in both the main fusebox (enginebay) and fuseboard by drivers right knee.

Car is a 1993 impreza WRX import