I agree that the resistor is the place to start with this issue, as it is the least expensive to replace. However the resistor did not fix my intermittent blower issue, it wound up being the control unit (the one in the center stack with the adjustment *****). There are several threads relating to these heater/AC issues here on the forum, and if memory serves there is one that gives instructions to test/troubleshoot before you start throwing money at it. Good Luck!