Pinpoint Test Y : The Blower Motor Is Inoperative - EATC: Notes
Refer to Automatic Climate Control System , for schematic and connector information.
Normal Operation and Fault Conditions
The BJB supplies voltage to the relay coil and relay switch contacts. When the blower motor relay coil receives a ground from the HVAC control module, the relay coil is energized and voltage is delivered to the blower motor and the blower motor speed control from the relay. The blower motor speed control has a dedicated ground. Ground for the blower motor is provided from the blower motor speed control. The HVAC control module sends a Pulse Width Modulated (PWM) signal to the blower motor speed control to determine the desired blower motor speed. The blower motor speed control varies the ground feed for the blower motor to control the speed.
DTC Fault Trigger Conditions
| DTC | Description | Fault Trigger Conditions |
|---|---|---|
| B10AF:12 | Blower Fan Relay: Circuit Short to Battery | This DTC sets when the HVAC control module senses voltage on the relay coil ground circuit when the relay is grounded by the HVAC control module, indicating a short directly to voltage. |
| B10AF:13 | Blower Fan Relay: Circuit Open | This DTC sets when the HVAC control module senses no voltage on the relay coil ground circuit when the relay is not grounded by the HVAC control module, indicating an open. |
| B10B9:12 | Blower Control: Circuit Short to Battery | This DTC sets when the HVAC control module senses excessive voltage on the variable motor control circuit for more than 1 second, indicating a short to voltage. Blower motor will be inoperative. |
| B10B9:14 | Blower Control: Circuit Short to Ground or Open | This DTC sets when the HVAC control module senses no voltage on the variable blower control circuit, indicating an open or a short directly to ground. Blower motor will be inoperative. |
Possible Sources
- Fuse
- Wiring, terminals or connectors
- Blower motor relay
- Blower motor speed control
- HVAC control module
- Blower motor
Visual Inspection and Diagnostic Pre-checks
- Inspect Battery Junction Box (BJB) fuses 32 (40A) and 57 (5A).