Test S: The Auxiliary Blower Motor Does Not Operate Correctly

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

S1-S2:

S2-S5:

S5-S8:

S8-S10:

S10 Continued:

S11-S12:

S13-S14:

Normal Operation
Under normal operation, ground for the blower motor is provided through circuit CHA06 (YE/VT) from the blower motor resistor. The blower resistor is grounded through circuit GD151 (BK/GN). The blower motor relay coils are supplied through circuit CBP46 (WH/BU). Blower motor speed is received by the electronic automatic temperature control (EATC) module or electronic manual temperature control (EMTC) module from the rear auxiliary control through circuit VHA17 (VT/GN). The blower speed selector resistor is provided reference voltage by the EMTC or EATC module through circuit LH111 (BN/WH) and ground through circuit RH111 (GY/BU). The auxiliary blower motor relay 1 coil receives ground from the EMTC or EATC module through circuit CH112 (VT/WH) if any blower speed but OFF is selected.

In LO, ground for the blower motor is provided through the blower motor resistor.

In MED-LO, blower motor relay 2 is grounded by the EMTC or EATC module through circuit CH114 (GN/WH). Blower motor ground circuit CHA06 (YE/VT) is connected through one half of the blower motor resistor to circuit CHA08 (GN/OG). Circuit CHA08 (GN/OG) is connected through blower motor speed relay 2 to the blower motor resistor through circuit CHA07 (BU/GY). The blower resistor is grounded through circuit GD151 (BK/GN).

In MED-HI, blower motor relay 3 is grounded by the EMTC or EATC module through circuit CH113 VT/GY). Blower motor ground circuit CHA06 YE/VT) is connected through blower motor relay 3 to circuit CHA08 (GN/OG). Circuit CHA08 GN/OG) is connected through one half of the blower motor resistor to the blower motor resistor to ground circuit GD151 (BK/GN).

In HI, blower motor relays 2 and 3 are grounded by the EMTC or EATC module through circuit CH114 (GN/WH) and CH113 (VT/GY). Blower motor ground circuit CHA06 (YE/VT) is connected through blower motor speed relay 3 to circuit CHA08 (GN/OG). Circuit CHA08 (GN/OG) is connected through blower motor relay 2 to the blower motor resistor ground circuit GD151 (BK/GN) by circuit CHA07 (BU/GY).

Possible Causes
- An open in circuit CH114 (GN/WH), CH113 (VT/GY), CBP46 (WH/BU), CHA08 (GN/OG), CHA07 (BU/GY) or CHA06 (YE/VT)
- A short to ground in circuit CH112 (VT/WH), CH114 (GN/WH), CH113 (VT/GY), CHA06 (YE/VT) or CHA08 (GN/OG)
- A short to voltage in circuit CHA05 (BN/WH)
- A short together in circuits CHA08 (GN/OG), CHA07 (BU/GY) and CHA06 (YE/VT)
- Auxiliary blower motor relay 1
- Auxiliary blower motor relay 3
- Auxiliary blower motor relay 2
- Auxiliary blower motor resistor
- EATC module
- EMTC module