AC has 5 power levels - 1-is fan and 2-5 is speed for AC. Problem is Fan nor AC does not turn on unless I turn the know to Level 4.
AC Knob Levels on 2003 Chevrolet Malibu
You need to go to your local autoparts store and replace the blower resistor. It is something you could do and it only cost around $25. It's under the dash on the passenger side. Eventually 4 and 5 will go out too.