Climate Control System

I have a 04 Chevy Colorado. The fan only works in the number 4 position. When the fan knob is in the 1, 2 or 3 positions, the fan does not run at all. Fuse looks OK.

Is #4 the highest setting? If so, then the most likely cause of the 1-3 outage is a bad fan resistor. There is some possibility that the switch itself is bad (though bad resistors are pretty common). You can find out what is going on with an electrical meter.

Yes, #4 is the highest setting. Great, I will check the resistor. I appreciate your prompt response. Thanks