heater a/c fan

I have a 2000 z71 and am having problems getting the heater and a/c fan switch to work in positions 1 and 2. I tried using a switch from another z71 (99) to no avail. The same results. In positions 3,4 and 5 the fan blows normally, just not in 1 and 2. Anyone had any similar problems and if so, know a remedy?

I Had A Simular Problem On My Wifes 99 Grand Am. There Is A Resistor Board Under Your Passenger Dash Board That Is Connected To Your Blower Motor. The Wires On The Board Is Burned Into.

Thanks for the infor cody07. I checked the resistor board/fan relay and discovered that the 1 & 2 position fusable link was burned. Replaced and everything works fine!