Test J: The Auxiliary Blower Motor Does Not Operate Correctly

PINPOINT TEST J: THE AUXILIARY BLOWER MOTOR DOES NOT OPERATE CORRECTLY

J1-J2:

J2-J5:

J5-J7:

J8-J10:

J11-J13:

J13-J14:

Normal Operation
Under normal operation, the auxiliary blower motor relay 1 coil receives a ground through circuit 57 (BK). The relay 1 coil receives voltage from circuit 752 (YE/RD) if any position but OFF is selected. Voltage is supplied to the relay 1 switch from circuit 884 (YE/BK). When the relay 1 coil is energized, voltage is delivered to the blower motor through circuit 371 (PK/WH). Ground for the motor is provided through circuit 261 (OG/BK) from auxiliary blower motor relay 2. In any speed except HI, ground is provided to relay 2 switch through the auxiliary resistor. Ground for the auxiliary resistor is provided by circuit 57 (BK). In HI, ground is provided to relay 2 switch through 57 (BK).

The auxiliary blower motor relay 2 coil receives voltage from circuit 752 (YE/RD) if any position but OFF is selected. When the auxiliary blower motor switch is in the HI position, ground is provided to the relay 2 coil through circuit 757 (RD/WH). When relay 2 is energized, the auxiliary blower motor is grounded directly through circuit 57 (BK).

Under normal operation, the auxiliary blower motor is provided a ground from the resistor through circuit 515 (OG/RD). The resistor gets a ground from the rear auxiliary blower switch, depending on selected speed, through circuit 752 (YE/RD) or circuit 751 (DB/WH). The rear auxiliary blower switch is provided ground through circuit 57 (BK).

Possible Causes
- An open in circuits 57 (BK), 515 (OG/RD), 751 (DB/WH), 752 (YE/RD) or 757 (RD/WH)
- A short to ground in circuits 261 (OG/BK), 515 (OG/RD), 751 (DB/WH), 752 (YE/RD) or 757 (RD/WH)
- A short to voltage in circuit 371 (PK/WH)
- A short together in circuits 515 (OG/RD), 751 (DB/WH) or 752 (YE/RD)
- Auxiliary blower motor switch
- Auxiliary blower motor resistor
- Auxiliary blower motor relay 1
- Auxiliary blower motor relay 2