when i turn on the heat,i get warm air from the dash but the air at floor level, on 2002 Dodge Ram 1500

i recently had a new heater core installed at the dealer about a month ago,this problem just occured yesterday,what is the likely causes

by in Kansas City, MO on February 16, 2013
1 answer
ANSWER by , February 17, 2013
'but the air at floor level,'....what? could you complete the question? And would it still be under warranty?More specific and complete details of problem will help get a better answer.