Heater problem
1999 Mercedes Benz C280 6 cyl Two Wheel Drive Automatic 133000 miles

my heat in the car only blows on the front window and the two side vents.It doesnt work on the feet or the center vents i call the dealership and they said it was the heatermotor behind the dash which would cost alot of time and money are they correct? is there any way of fixing it cheap?can i go and take the vent flaps out so it blows through all vents