Pinpoint Test Y: The Blower Motor is Inoperative - DATC
Climate Control System
Pinpoint Tests
Pinpoint Test Y: The Blower Motor is Inoperative - 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:12 (Blower Fan Relay: Circuit Short to Battery) - the module senses excessive voltage on the relay coil ground circuit when the module is grounding the circuit for more than 2 seconds.
- DTC B10AF:13 (Blower Fan Relay: Circuit Open) - the module senses no voltage on the relay coil ground circuit when the module is grounding the circuit for more than 2 seconds.
- 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:
- Fuse(s)
- Wiring, terminals or connectors
- Blower motor relay
- Blower motor speed control
- HVAC module
- Blower motor
PINPOINT TEST Y: THE BLOWER MOTOR IS INOPERATIVE - DATC
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Y1 CHECK THE HVAC MODULE FOR DTCs
- Ignition ON.
- Check the HVAC module for DTCs.
- Are any DTCs present?
Yes
For B10AF:12, GO to Y2.
For DTC B10AF:13, CARRY OUT the Blower Motor Relay component test.
If the relay tests OK, GO to Y3.
For DTC B10B9:14, GO to Y5.
No
For vehicles with navigation, GO to Y6.
For vehicles without navigation, GO to Y7.
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Y2 CHECK THE BLOWER MOTOR RELAY COIL SWITCHED GROUND CIRCUIT FOR A SHORT TO VOLTAGE
- 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 any voltage present?
Yes
REPAIR circuit CH123 (VT/GN) for a short to voltage. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
No
GO to Y16.
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Y3 CHECK THE BLOWER MOTOR RELAY COIL SUPPLY VOLTAGE
- Ignition OFF.
- Disconnect: Blower Motor Relay.
- Ignition ON.
- Measure the voltage between blower motor relay socket pin 1, circuit CBB52 (GN/WH) and ground.
- Is the voltage greater than 10 volts?
Yes
GO to Y4.
No
VERIFY Battery Junction Box (BJB) fuse 52 (5A) is OK. If OK, REPAIR circuit CBB52 (GN/WH) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short. Diagrams By Number
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Y4 CHECK THE BLOWER MOTOR RELAY COIL SWITCHED GROUND CIRCUIT FOR AN OPEN
- Ignition OFF.
- Disconnect: HVAC Module - DATC C228A/C2109A.
For vehicles without navigation
- For vehicles without navigation, measure the resistance between blower motor relay socket pin 2, circuit CH123 (VT/GN) and HVAC module - EMTC C2109A-11, circuit CH123 (VT/GN), harness side.
For vehicles with navigation
- For vehicles with navigation, measure resistance between blower motor relay socket pin 2, circuit CH123 (VT/GN) and HVAC module - EMTC C228A-24, circuit CH123 (VT/GN), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to Y16.
No
REPAIR circuit CH123 (VT/GN) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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Y5 CHECK THE BLOWER MOTOR CONTROL CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: HVAC Module - DATC C228A/C2109A.
- Disconnect: Blower Motor Speed Control C271.
- Measure the resistance between blower motor speed control C271-3, circuit VH101 (WH/VT), harness side and ground.
- Is the resistance greater than 10,000 ohms?
Yes
GO to Y15.
No
REPAIR circuit VH101 (WH/VT) for a short to ground. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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Y6 CHECK THE BLOWER MOTOR OPERATION USING THE BLOWER MOTOR SPEED (BLOWRSPD) ACTIVE COMMANDS
- 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 Y7.
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Y7 CHECK THE HVAC MODULE BLOWER MOTOR RELAY OUTPUT
NOTICE: The following step uses a test light to simulate normal circuit loads. Use only the test light recommended in the Special Tools table at the beginning or equivalent. To avoid connector terminal damage, use the Flex Probe Kit for the test light probe connection to the vehicle. Do not use the test light probe directly on any connector.
- Ignition OFF.
- Disconnect: Blower Motor Relay.
- Ignition ON.
- Connect the 12-volt test light between blower motor relay socket pin 1, circuit CBB52 (GN/WH) and socket pin 2, circuit CH123 (VT/GN).
- Select PANEL on the HVAC controls.
- Does the test light illuminate?
Yes
GO to Y8.
No
GO to Y16.
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Y8 CHECK THE BLOWER MOTOR RELAY SWITCH CONTACT VOLTAGE CIRCUIT FOR AN OPEN
- Measure the voltage between blower motor relay socket pin 3, circuit SBB51 (BU/RD) and ground.
- Is the voltage greater than 10 volts?
Yes
GO to Y9.
No
VERIFY Battery Junction Box (BJB) fuse 51 (40A) is OK. If OK, REPAIR circuit SBB51 (BU/RD) for an open. TEST the system for normal operation. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short. Diagrams By Number
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Y9 CHECK THE BLOWER MOTOR RELAY
- Connect fused jumper lead between blower motor relay socket pin 3, circuit SBB51 (BU/RD) and socket pin 5, circuit CH402 (YE/GN).
- Does the blower motor operate?
Yes
INSTALL a new blower motor relay. TEST the system for normal operation.
No
GO to Y10.
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Y10 CHECK FOR VOLTAGE TO THE BLOWER MOTOR
- Ignition OFF.
- Disconnect: Blower Motor C2004.
- Connect: Blower Motor Relay.
- Ignition ON.
- Select PANEL on the HVAC controls.
- Measure the voltage between blower motor C2004-1, circuit CH402 (YE/GN), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to Y11.
No
REPAIR circuit CH402 (YE/GN) for an open. TEST the system for normal operation.
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Y11 CHECK THE BLOWER MOTOR GROUND CIRCUIT FOR AN OPEN
- Ignition OFF.
- Disconnect: Blower Motor Speed Control C271.
- Measure the resistance between blower motor C2004-2, circuit VH301 (YE/BU), harness side and blower motor speed control C271-2, circuit VH301 (YE/BU), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to Y12.
No
REPAIR circuit VH301 (YE/BU) for an open. TEST the system for normal operation.
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Y12 CHECK THE BLOWER MOTOR SPEED CONTROL GROUND CIRCUIT FOR AN OPEN
- Measure the resistance between blower motor speed control C271-1, circuit GD138 (BK/WH), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
GO to Y13.
No
REPAIR circuit GD138 (BK/WH) for an open. TEST the system for normal operation.
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Y13 CHECK FOR VOLTAGE TO THE BLOWER MOTOR SPEED CONTROL
- Ignition ON.
- Select PANEL on the HVAC controls.
- Measure the voltage between blower motor speed control C271-4, circuit CH402 (YE/GN), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to Y14.
No
REPAIR circuit CH402 (YE/GN) for an open. TEST the system for normal operation.
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Y14 CHECK THE BLOWER MOTOR
- Ignition OFF.
- Connect: Blower Motor C2004.
- Connect a fused jumper lead between blower motor speed control C271-2, circuit VH301 (YE/BU), harness side and C271-1, circuit GD138 (BK/WH), harness side.
- Ignition ON.
- Select PANEL on the HVAC controls.
- Does the blower motor operate?
Yes
GO to Y15.
No
INSTALL a new blower motor. REFER to Climate Control Service and Repair. TEST the system for normal operation.
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Y15 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 Y16.
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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Y16 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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