chevrolet fan 1500 hd silverado?

[mrnepa]

i have a 2003 silverado my fan for any setting only works n 4 and 5 i cannot get low settings someone told me there is a part that has to be replaced under the dash but i cannot remember the name of it, he said it began with a R can someone help me

 

[r_sontag]

You need to replace the resistor. It extends into the air box under the dash and it allows for slower fan speeds. When the fan motor has 12 volts applied to it, it runs at full speed. In order to get slower speeds,a resistor is needed. The resistor lowers the voltage below 12 volts and this allows the fan to turn slower. The problem is this also creates heat in the resistor,since it is burning off the extra voltage. That is why it is mounted on the airbox. When you remove it,you will see that the resistor coils are located in the air stream to cool it. Hope this helps.