01' 1500 the fan only works on high speed. I imagine the switch needs to be replaced, am I correct ? Is this a major job?

Thanks
Ray

 

the problem is not the switch, it's a resistor gone bad. Under the dash on the passenger side on the blower motor assembly(black plactic air box)on the very bottom next to the floor there will be a small black looking plate with 2 screws holding it into place of the blower assembly and an electrical plug. Remove the plug and the two screws to remove the sub assembly, you can buy the whole part at a dealer for thes than 20 dollars. Reinstall and you should be good to go. When its removed, there should be little wire coils on it, these are what controls the different speeds of the blowe[sm=shades.gif]r motor

 

it could very well be the resistor, but that wasn't so in my case. i have a 97 sierra and the problem was a melted wire harness behind the blower control dial. the clip that goes to the wiring harness and the clip that plugs into the back of the blower control dial were both melted. this is a common problem from what i've heard. I went to a wrecker and got both pieces from a write off that weren't melted and installed them today, blower works on all speeds ... for now. MUCH EASIER TO DO THAN the resistor or motor. just some snipping and soldering.