Pinpoint Test U: The Blower Motor Does Not Operate Correctly - DATC
Climate Control System
Pinpoint Test U: The Blower Motor Does Not Operate Correctly - DATC
Refer to Wiring Diagram Set 55, Automatic Climate Control System for schematic and connector information. Diagrams By Number
Normal Operation
Under normal operation, the blower motor relay coil receives a ground from the HVAC 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 SBB35 (BU/RD). When the relay coil is energized, voltage is delivered to the blower motor and the blower motor speed control through circuit CH402 (YE/GN). Ground for the motor is provided through circuit VH301 (YE/BU) from the blower motor speed control. Ground for the blower control module is provided by circuit GD138 (BK/WH). The HVAC module sends a Pulse-Width Modulation (PWM) signal to the blower motor speed control through circuit VH101 (WH/VT) to control the blower speed.
- DTC B10AF:11 Blower Fan Relay: Circuit Short to Ground - The module senses no voltage on the relay coil ground circuit, indicating a short directly to ground.
- DTC B10B9:12 Blower Control: Circuit Short to Battery - 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:
- Fuse(s)
- Wiring, terminals or connectors
- Blower motor speed control
- HVAC module - Dual Automatic Temperature Control (DATC)
PINPOINT TEST U: THE BLOWER MOTOR DOES NOT OPERATE CORRECTLY - DATC
U1-U5:
U5-U6:
U6-U8:
