Blower resistor

Recently the blower in my 03 silverado started working only on the highest setting. So I assumed that it was the resistor pack and replaced it. THat gave me back blower # 2-5, but not #1. But all of the other speeds worked fine, then the nex day when I went out I had lost # 1-4 again. Could this be my blower motor going out and burnig up the resistor pack? Or is there something else that I am overlooking?

In most cases anytime that you get into a situation where the blower motor loses speeds due to a resistor you will always replace the blower motor and blower motor resistor. Secondly you should check and see if you have a cabin air filter and if you do replace it(clogged filter='s burned up blower motor)---I have seen some cases where the circuit get so burned that the actual control head needs to be replaced. let me know if this helps. P.S. I have also seen where the 7-pin connector to the resistor gets melted also--please check these things.