05 Pathfinder fan not working on "1" while A/C not working om "2,3,4"

Hi,

The fan om my '05 Pathfinder does not work on setting 1, but the A/C will work passively when driving at speed. The fan will function on settings 2,3,and 4, but the A/C will not work/turn on for those fan settings. I've tried replacing the heater/fan control unit in the dash and all fuses appear ok. I don't want to take the car into a dealer if I do not have to. Has anyone had this problem? or Can you help?

Thank you