Test M: The Blower Motor Is Inoperative
PINPOINT TEST M: THE BLOWER MOTOR IS INOPERATIVENormal Operation
Under normal operation, the blower motor relay coil receives voltage through circuit 181 (BN/OG). The coil receives ground from the HVAC module through circuit 364 (BK/LG) if any position but OFF is selected. Voltage is supplied to the relay switch contact through circuit 181 (BN/OG). When the relay coil is energized, voltage is delivered to the blower motor through circuit 371 (PK/WH). Ground for the motor is provided through circuit 515 (OG/RD) from the blower motor speed control. Ground for the blower motor speed control is provided by circuit 57 (BK).
The blower motor speed control receives a 1-2 volt signal from the HVAC module through circuit 752 (YE/RD) to determine the desired blower motor speed. The HVAC module receives a feedback voltage from the blower motor speed control through circuit 260 (RD/OG) to determine actual blower motor speed. When the highest blower motor setting is selected, the HVAC module sends 12 volts to the blower motor speed control through circuit 754 (LG/WH).
This pinpoint test is intended to diagnose the following:
- Fuse(s)
- Wiring, terminals or connectors
- Blower motor
- Blower motor relay
- Blower motor speed control
- HVAC module
M1-M3:
M3-M5:
M5-M7:
M7-M8:
M8-M10:
M10-M12:
