Pinpoint Test Z: The Blower Motor Does Not Operate Correctly - DATC
Climate Control System
Pinpoint Tests
Pinpoint Test Z: 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
Voltage is supplied to the relay coil from Battery Junction Box (BJB) fuse 52 (5A) and relay switch contacts from BJB fuse 51 (40A). When the blower motor relay coil receives a ground from the HVAC module, the relay coil is energized and voltage is delivered to the blower motor and the blower motor speed control from the relay. Ground for the motor is provided from the blower motor speed control. Ground is provided for the blower control module. The HVAC module sends a Pulse Width Modulated (PWM) signal to the blower motor speed control 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 when the module is not grounding the circuit for more than 2 seconds.
- DTC B10B9:12 (Blower Control: Circuit Short to Battery) - the module senses excessive voltage on the blower motor control PWM circuit for more than 1 second.
- DTC B10B9:14 (Blower Control: Circuit Short to Ground or Open) - the module senses no voltage on the blower motor control PWM circuit for more than 1 second.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Blower motor speed control
- HVAC module
- Front Controls Interface Module (FCIM)
PINPOINT TEST Z: THE BLOWER MOTOR DOES NOT OPERATE CORRECTLY - DATC
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Z1 CHECK THE HVAC MODULE FOR DTCs
- Ignition ON.
- Check the HVAC module for DTCs.
- Are any DTCs present?
Yes
For DTC B10AF:11, GO to Z2.
For DTC B10B9:12, GO to Z3.
For DTC B10B9:14, GO to Z4.
No
For vehicles with navigation, GO to Z5.
For vehicles without navigation, GO to Z6.
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Z2 CHECK THE BLOWER MOTOR RELAY COIL SWITCHED GROUND CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: Blower Motor Relay.
- Disconnect: HVAC Module - DATC C228A/C2109A.
- Ignition ON.
- Measure the voltage between blower motor relay socket pin 2, circuit CH123 (VT/GN) and ground.
- Is the resistance greater than 10,000 ohms?
Yes
GO to Z11.
No
REPAIR circuit CH123 (VT/GN) for a short to ground. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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Z3 CHECK THE BLOWER MOTOR CONTROL CIRCUIT FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: Blower Motor Speed Control C271.
- Disconnect: HVAC Module - DATC C228A/C2109A.
- Ignition ON.
- Measure the voltage between blower motor speed control C271-3, circuit VH101 (WH/VT), harness side and ground.
- Is any voltage present?
Yes
REPAIR circuit VH101 (WH/VT) for a short to voltage. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
No
GO to Z10.
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Z4 CHECK THE BLOWER MOTOR CONTROL CIRCUIT FOR AN OPEN
- Ignition OFF.
- Disconnect: Blower Motor Speed Control C271.
- Disconnect: HVAC Module - DATC C228A/C2109A.
For vehicles without navigation
- For vehicles without navigation, measure the resistance between blower motor speed control C271-3, circuit VH101 (WH/VT), harness side and HVAC module - DATC C2109A-1, circuit VH101 (WH/VT), harness side.
For vehicles with navigation
- For vehicles with navigation, measure the resistance between blower motor speed control C271-3, circuit VH101 (WH/VT), harness side and HVAC module - DATC C228A-14, circuit VH101 (WH/VT), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to Z10.
No
REPAIR circuit VH101 (WH/VT) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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Z5 CHECK THE BLOWER MOTOR OPERATION USING THE BLOWER MOTOR SPEED (BLOWRSPD) ACTIVE COMMAND
- Enter the following diagnostic mode on the scan tool: HVAC Module DataLogger.
- Select PANEL mode on the HVAC controls.
- Select the lowest blower motor setting.
- Observe blower motor speed while using the scan tool to operate the HVAC module active command BLOWRSPD, increasing and decreasing the percentage value.
- Does the blower motor speed change between low and high when the active command is changed?
Yes
INSTALL a new Front Controls Interface Module (FCIM). REFER to Information and Entertainment Systems Front Controls Interface Module (FCIM). TEST the system for normal operation.
No
GO to Z6.
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Z6 VERIFY THE BLOWER MOTOR OPERATION
- Ignition ON.
- Select PANEL on the HVAC controls. Adjust the blower motor setting to LO and then to HI then press the POWER button on the HVAC module (OFF).
- Does the blower motor operate at any setting and/or turn OFF?
Yes
If the blower motor operates always in HI, GO to Z7. If the blower motor is always ON, GO to Z8. All other symptoms, INSTALL a new blower motor speed control. REFER to Climate Control Service and Repair. TEST the system for normal operation. If the blower motor still does not operate correctly, GO to Z11.
No
GO to Pinpoint Test Y. Pinpoint Test Y: The Blower Motor is Inoperative - DATC
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Z7 CHECK THE BLOWER MOTOR PWM GROUND CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: Blower Motor Speed Control C271.
- Disconnect: Blower Motor C2004.
- Measure the resistance between blower motor connector C2004-2, circuit VH301 (YE/BU), harness side and ground.
- Is the resistance greater than 10,000 ohms?
Yes
GO to Z10.
No
REPAIR circuit VH301 (YE/BU) for a short to ground. TEST the system for normal operation.
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Z8 CHECK THE BLOWER MOTOR RELAY
- Ignition OFF.
- Disconnect: Blower Motor Relay.
- Turn OFF the HVAC system.
- Does the blower motor operate?
Yes
GO to Z9.
No
INSTALL a new blower motor relay. TEST the system for normal operation.
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Z9 CHECK THE BLOWER MOTOR VOLTAGE CIRCUIT FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: Blower Motor C2004.
- Ignition ON.
- Measure the voltage between blower motor C2004-1, circuit CH402 (YE/GN), harness side and ground.
- Is any voltage present?
Yes
REPAIR circuit CH402 (YE/GN) for a short to voltage. TEST the system for normal operation.
No
GO to Z10.
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Z10 CHECK THE BLOWER MOTOR SPEED CONTROL CONNECTION
- Inspect the blower motor speed control connector for:
- corrosion
- pushed-out terminals
- damaged terminals
- Connect and correctly seat the blower motor speed control connector connector.
- Clear the DTCs.
- Enter the following diagnostic mode on the scan tool: Self-Test - HVAC Module.
- Operate the system and verify the concern is still present.
- Is the concern still present?
Yes
INSTALL a new blower motor speed control. REFER to Climate Control Service and Repair. TEST the system for normal operation. If the blower motor is still inoperative, GO to Z11.
No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.
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Z11 CHECK THE HVAC MODULE CONNECTION
- Inspect the HVAC module connectors for:
- corrosion
- pushed-out terminals
- damaged terminals
- Connect and correctly seat all the HVAC module connectors.
- Clear the DTCs.
- Enter the following diagnostic mode on the scan tool: Self-Test - HVAC Module.
- Operate the system and verify the concern is still present.
- Is the concern still present?
Yes
INSTALL a new HVAC module. REFER to Climate Control Service and Repair. 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.
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