Details: The tech inspected the fuses and relays for the air compressor and blower motor. All of them were found to be good. He then traced the power wire to the motor to check for B+ power – there was power to the motor. Next, he unplugged the harness from the blower motor resistor and found the power wire pin was burnt and melted.
Confirmed Repair: The tech replaced the resistor and installed a new wiring harness pigtail. He retested the blower motor and it was operating on all fan speeds.