Test O: The Blower Motor Does Not Operate Correctly - EATC

PINPOINT TEST O: THE BLOWER MOTOR DOES NOT OPERATE CORRECTLY - EATC

O1-O3:

O3-O4:

O5-O7:

O7-O8:

O9:

Normal Operation
Under normal operation, the blower motor relay coil receives a ground from the electronic automatic temperature control (EATC) module through circuit CH123 (VT/GN). The coil receives ignition voltage through circuit CBP45 (YE). Voltage is supplied to the relay switch contact through circuit CH402 (YE/GN)/(BK). When the relay coil is energized, voltage is delivered to the blower motor control module through circuit CH402 (YE/GN)/(BK). Ground for the blower control module is provided by circuit GD116 (BK/VT)/(BK/RD). The EATC module provides a blower target speed signal to the blower control module through circuit VH101 (WH/VT)/(RD) to control the blower speed. The actual blower speed signal is provided to the EATC module through circuit CH102 (YE/BU)/(BN) from the blower control module. Ground for the motor is provided through circuit (BU) from the blower control module.

Possible Causes
- An open in circuit CH102 (YE/BU)/(BN)
- A short to ground in circuit VH101 (WH/VT)/(RD), CH102 (YE/BU)/(BN), (BU) or CH402 (YE/GN)/(BK)
- A short to voltage in circuit VH101 (WH/VT)/(RD), CH102 (YE/BU)/(BN), (BU) or CH402 (YE/GN)/(BK)
- A short together in circuits VH101 (WH/VT)/(RD) and CH102 (YE/BU)/(BN)
- Blower motor control module
- Blower motor relay
- EATC module