No Blower Motor Control

1. Defective blower motor resistor.
2. Defective blower switch.
3. Defective in-car and/or ambient temperature sensors.
4. Defective rheostat.
5. Defective servo motor.
6. Defective vacuum valves.
7. Defective blower control relay.
8. Defective amplifier.
9. Defective heater mode switch.
10. Defective coolant temperature switch.
11. Defective wiring or ground connections.
12. Defective vacuum circuit.