Blower Motor Resistor: Testing and Inspection

Inspection

1. Disconnect the negative (-) battery terminal.
2. Remove the power mosfet. Measure drain-to-sauce resistance of the power mosfet.









3. If the measured resistance is not specification, replace the power mosfet.
4. If measured resistance is specification, install power mosfet and ignition switch ON. Measure the voltage between blower motor terminals by operating control switch manually.
5. Select the control switch to raise voltage until high speed.




Specification





6. If the measured voltage is not specification, substitute with a known-good power mosfet and check for proper operation.
7. If the problem is corrected, replace the power mosfet.