I have a 99 tahoe 4x4 LT. I just purchased it a few weeks ago. I love it, just have some little things to fix on it. I think my heater blower motor is going out but want to see what you all think. When driving or at idle with the blower on hi , low or any other setting the blower will just slow down for no reason then go back on to what it was set at. Also I get a thug sound like a damper door (or whatever it is called) inside the blower motor area keeps opening and closing. I have never changed out the blower motor in one of these is it difficult or pretty straight foreward? Any ideas or help would be great. Thank you