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

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

Q1-Q4:

Q4-Q5:

Q6-Q7:

Q8:

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 CBB67 (GN/BN). Voltage is supplied to the relay switch contact. When the relay coil is energized, voltage is delivered to the blower motor and the blower motor control module through circuit CH402 (YE/GN). Ground for the motor is provided through circuit VH301 (YE/BU) from the blower control module. Ground for the blower control module is provided by circuit GD138 (BK/WH). The EATC module sends pulse a width modulated signal to the blower control module through circuit VH101 (WH/VT) to control the blower speed.

Possible Causes
- An open in circuit VH101 (WH/VT)
- A short to ground in circuit VH301 (YE/BU) or circuit CH123 (VT/GN)
- A short to voltage in circuit VH101 (WH/VT) or circuit CH402 (YE/GN)
- Blower motor control module
- EATC module