So i have had this problem for over a year and have been too lazy/broke to fix it....i have a 2005 regular cab base model v6 silverado. The heater/AC only seem to work when i am on the throttle and the more i am the more it'll blow. The different levels 1-5 dont seem to control anything. Anyone else run into this? Know of a solution or cost of it if i take it to the stealership?