Test O: The Blower Motor Does Not Operate Correctly - EATC
PINPOINT TEST O: THE BLOWER MOTOR DOES NOT OPERATE CORRECTLY - EATCNormal Operation
Under normal operation, the blower motor relay coil receives 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 speed control module through circuit CH402 (YE/GN). Ground for the motor is provided through circuit VH301 (YE/BU) from the blower speed control module. Ground for the blower motor speed control module is provided by circuit GD112 (BK/GN). The EATC module sends a pulse width modulation (PWM) signal to the blower motor speed control module through circuit VH101 (WH/VT) to control the blower speed.
- DTC B12B1 Front Blower Motor PWM Drive Circuit Shorted to Voltage - The module senses excessive voltage on the blower motor control PWM circuit, indicating a short directly to voltage.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Blower motor speed control module
- EATC module
O1-O4:
O4-O6:
O6-O7:
O7-O8:
