2002 Pontiac Grand Prix Heater only works on setting 4 or 5

I have a 2002 Pontiac Grand Prix that has always had a heat issue. At first all settings on the dial worked from lowest or one to the highest or five but a few years back it stopped working at the lower settings and would only turn on when I turned it to a three or higher. Now it started working at a four and nothing lower. At first I thought it was the cheap plastic dial itself that have broken in the past but at this point I am not sure. I have however considered it to be a possible blower motor issue, which if it is could you please tell me where it is located on this year. Thanks for your time.