2002 Pontiac Grand Prix fan switch

My first thought is the resistor assembly.

The blower motor and resistor assembly should be located under the passenger side of the dash.

The high speed doesn't use a resistor. You might check the fuses. One for hvac control, that circuit goes hot when you turn on the key.

Hvac high fuse is hot all the time. That one should be ok, the blower works on high, correct?