THE SELECTOR SWITCH FOR THE HEAT AND AIR FAN ON THE CONSOLE ONLY WORKS ON #4

The resistor pack is possibly bad. I had a friend with this problem on his grand prix. 1, 2, and 3 also disabled the automatic daytime running lights and the heated seats didn't work either. It turned out to be the ignition switch was bad. Is there possibly another symptom that the car is having that you overlooked? If there are no other symptoms then its most likely the resistor pack. #4 bypasses all resistors. #3 runs through resistor a #2 runs through a and b and setting 1 runs through a, b, and c. If resistor a goes bad you loose all 3 settings and so-on. If its not integrated into the control unit then you can easily remove it and test it. With a test light.

how to replace heater blower switch on a pontiac g6 2005