Testing a blower motor resistor

Check for twelve volts feeding the assembly on one of the wires. If it is there, check for voltage on the blower motor wires. One must have some voltage and one must have zero volts. You will need to back-probe the wires in their connectors because these voltages must be taken with everything plugged in to be valid.

You can also do a resistance check, but for that, the assembly must be removed, then look for the thermal fuse. That is what must be checked for continuity. If the thermal fuse is open, it is because the fan motor is tight and was drawing high current. Replace the motor, otherwise the thermal fuse in the new resistor assembly will burn open.

So what speeds does it not work on? That blower is hard to get to.