How do I locate and replace resistor block?

 

Usually the resistor block is held in place with 2 screws. It is generally placed in the ductwork to cool the resistors and is usually located under the hood in the engine compartment on the passenger side of the firewall. It will have a plug with at least 3 wires on it. If you have purchased a replacement , that should make it easier to spot since you will know what to look for.