Pinpoint Test S: The Auxiliary Blower Motor Does Not Operate Correctly
Climate Control System
Pinpoint Tests
Pinpoint Test S: The Auxiliary Blower Motor Does Not Operate Correctly
Refer to Wiring Diagram Set 52, Auxiliary Climate Control for schematic and connector information. Diagrams By Number
Refer to Wiring Diagram Set 54, Manual Climate Control System for schematic and connector information. Diagrams By Number
Refer to Wiring Diagram Set 55, Automatic Climate Control System for schematic and connector information. Diagrams By Number
Under normal operation, the blower motor relay coil receives a ground from the HVAC module through circuit CH112 (VT/WH). The coil receives ignition voltage through circuit CBP43 (GY). Voltage is supplied to the relay switch contact through circuit SBB13 (WH/RD). When the relay coil is energized, voltage is delivered from the relay to the blower motor control module through circuit CHA02 (BN/GN). Ground for the blower control module is provided by circuit GD149 (BK/GY). The HVAC module provides a Pulse-Width Modulation (PWM) signal to the blower control module through circuit VHA25 (BN/VT) to control the blower speed. Voltage for the motor is provided through circuit VH301 (YE/BU) from the blower control module. Ground for the motor is provided through circuit VHA19 (BN) from the blower control module.
- DTC B10BA:12 Rear Blower Control: Circuit Short to Battery - The module senses excessive voltage on the relay coil ground circuit, indicating a short directly to voltage.
- DTC B11EC:11 Rear HVAC Blower Control input: Circuit Short to Ground - The module senses a short directly to ground in the auxiliary blower control input to the HVAC module.
- DTC B11EC:15 Rear HVAC Blower Control input: Circuit Short to Battery or Open - The module senses an open/short to voltage in the auxiliary blower control input to the HVAC module.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- HVAC module
- Auxiliary climate control assembly
- Auxiliary blower motor speed control
- Auxiliary blower motor relay
PINPOINT TEST S: THE AUXILIARY BLOWER MOTOR DOES NOT OPERATE CORRECTLY
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S1 CHECK THE HVAC MODULE FOR DTCs
- Ignition ON.
- Check the HVAC module for DTCs.
- Are DTCs present?
Yes
For DTC B10B0:14, REPAIR circuit CH112 (VT/WH) for a short to ground. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
For DTC B10BA:14, REPAIR circuit VHA25 (BN/VT) for a short to ground. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
For DTC B11EC:11, GO to S5.
For DTC B11EC:15, GO to S6.
No
CARRY OUT the auxiliary blower motor relay component test.
If the relay tests OK, GO to S2.
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S2 CHECK CIRCUIT CHA02 (BN/GN) FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: Auxiliary Blower Motor Speed Control C3002a.
- Disconnect: Auxiliary Blower Motor Relay.
- Ignition ON.
- Measure the voltage between ground and auxiliary blower motor speed control C3002a-6, circuit CHA02 (BN/GN), harness side.
- Is any voltage present?
Yes
REPAIR circuit CHA02 (BN/GN) for a short to voltage. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
No
GO to S3.
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S3 CHECK CIRCUIT VHA19 (BN) FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: Auxiliary Blower Motor Speed Control C3002b.
- Disconnect: Auxiliary Blower Motor C3021.
- Measure the resistance between ground and auxiliary blower motor C3002b-2, circuit VHA19 (BN), harness side.
- Is the resistance greater than 10,000 ohms?
Yes
GO to S4.
No
REPAIR circuit VHA19 (BN) for a short to ground. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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S4 CHECK THE BLOWER MOTOR
- Connect: Auxiliary Blower Motor C3021.
- Ignition ON.
- Connect a fused jumper lead between auxiliary blower motor speed control C3002a-6, circuit CHA02 (BN/GN), harness side and C3002b-1, circuit VH301 (YE/BU), harness side.
- Connect a fused jumper lead between auxiliary blower motor speed control C3002a-5, circuit GD149 (BK/GY), harness side and C3002b-2, circuit VHA19 (BN), harness side.
- Does the blower motor operate at high speed?
Yes
INSTALL a new auxiliary blower motor speed control. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation. If the blower motor still operates incorrectly, GO to S8.
No
INSTALL a new auxiliary blower motor. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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S5 CHECK CIRCUIT VHA17 (VT/GN) FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: Auxiliary Climate Control Assembly C3198.
- Disconnect: HVAC Module C228b.
- Measure the resistance between ground and HVAC module C228b-17, circuit VHA17 (VT/GN), harness side.
- Is the resistance greater than 10,000 ohms?
Yes
INSTALL a new auxiliary climate control assembly. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation. If the blower motor still operates incorrectly, GO to S8.
No
REPAIR circuit VHA17 (VT/GN) for a short to ground. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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S6 CHECK CIRCUIT VHA17 (VT/GN) FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: Auxiliary Climate Control Assembly C3198.
- Disconnect: HVAC Module C228b.
- Ignition ON.
- Measure the voltage between ground and HVAC module C228b-17, circuit VHA17 (VT/GN), harness side.
- Is any voltage present?
Yes
REPAIR circuit VHA17 (VT/GN) for a short to voltage. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
No
GO to S7.
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S7 CHECK CIRCUIT VHA17 (VT/GN) FOR AN OPEN
- Ignition OFF.
- Measure the resistance between HVAC module C228b-17, circuit VHA17 (VT/GN), harness side and auxiliary climate control assembly C3198-4, circuit VHA17 (VT/GN), harness side.
- Is the resistance less than 5 ohms?
Yes
INSTALL a new auxiliary climate control assembly. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation. If the blower motor still operates incorrectly, GO to S8.
No
REPAIR circuit VHA17 (VT/GN) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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S8 CHECK MODULE CONNECTION
- Carry out the HVAC Module Cold Boot Process. HVAC Module Cold Boot Process
- Carry out the HVAC Module On-Demand Self Test. Alternate Diagnostic Methods - HVAC Module
- Operate the system.
- Does the concern return?
Yes
INSTALL a new HVAC module. TEST the system for normal operation.
No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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