AC/Heater control only works on high is changing it out best way to go??

Napa has 4 different blower motor resistors available for your GMC and usually if the fan only works on high then the resistor is bad, you can see them here http://www.napaonline.com/Catalog/Result.aspx?Ntt=blower&Ntk=Keyword&Nty=1&N=599001+102004+50030+2030042 and about 1/2 hour to replace this