Where is the blower motor resistor on a 2004 Colorado?

The blower fan resistor is located in the foot well of the passenger seat (under the glove box). Remove the two screws and pull the resistor down and out. Unplug the resistor and look at the metal contact points. If they are burnt out you might have to replace the plug and resistor. Replacing the plug requires light electrical work involving crimping/splicing wires.