Test N: The Blower Motor Is Inoperative - EATC
PINPOINT TEST N: THE BLOWER MOTOR IS INOPERATIVE - 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 motor 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 modulated signal to the blower motor speed control module through circuit VH101 (WH/VT) to control the blower speed.
- DTC B12AF Front Blower Motor Relay Drive Circuit Shorted to Battery Voltage - The module senses excessive voltage on the relay coil ground circuit, indicating a short directly to voltage.
- DTC B12B0 Front Blower Motor Relay Drive Circuit Open or Shorted to Ground - The module senses no voltage on the relay coil ground circuit, indicating an open or a short directly to ground.
- DTC B12B2 Front Blower Motor PWM Drive Circuit Open or Shorted to Ground - The module senses no voltage on the blower motor control pulse width modulation (PWM) circuit, indicating an open or a short directly to ground.
This pinpoint test is intended to diagnose the following:
- Fuse(s)
- Wiring, terminals or connectors
- Blower motor relay
- Blower motor speed control module
- Blower motor
- EATC module
N1-N2:
N2-N4:
N4-N6:
N6-N8:
N9-N11:
N11 Continued:
N12-N13:
