I have a 2002 Honda Accord and the heater blower will only work on the two higher speeds out of the four available. From reading the posts here, I believe the problem to be the blower resistor. Where is that located on this model???

 

On the passenger side under the dashboard toward the front, located under the blower assembly, held on with two screw.

Go to slhonda.com, wholesale parts, to see the item. Under Electrical, Heater Blower. Part is not cheap.