i got a fault with the heater motor on my 200tdi and was wondering if anyone can help me ?

first of all it dont work sometimes untill i thump or kick the lower dashboard and then the speed isnt constant , it either works fine or barely blows anything even on full speed
sometimes as well i can hear wot sounds like the indicator relay going crazy when the fan is on full speed .
can anyone give me any ideas as its getting a bit cold to keep the window open to stop the car steaming up
thanks

sounds like a relay ..my heater blowers gone but i dont have anything on any power setting but thats most likely the heater relay faulty me thinks . i no what ya meen havin to keep the window open ..tisnt fun