Pinpoint Test S: The Blower Motor Is Inoperative - DATC
Climate Control System
Pinpoint Tests
Pinpoint Test S: 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
Under normal operation, the blower motor relay coil receives a ground from the HVAC module - Dual Automatic Temperature Control (DATC). The blower motor relay coil is provided voltage. Voltage is supplied to the blower motor relay switch contact. When the blower motor relay blower motor relay coil is grounded by the DATC, the blower motor relay is energized and voltage is delivered to the blower motor control module. Ground for the blower motor speed control is provided. The HVAC module - DATC provides a blower target speed signal to the blower motor speed control to control the blower speed. The actual blower speed signal is provided to the HVAC module - DATC from the blower motor speed control. Ground for the motor is provided from the blower motor speed control.
This pinpoint test is intended to diagnose the following:
- Fuse(s)
- Wiring, terminals or connectors
- Blower motor relay
- Blower motor speed control
- HVAC module - DATC
- Blower motor
PINPOINT TEST S: THE BLOWER MOTOR IS INOPERATIVE - DATC
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S1 VERIFY THE BLOWER MOTOR OPERATION
- Ignition ON.
- Press the PANEL button on the HVAC module - DATC. Adjust the blower motor setting to LO and then to HI.
- Is the blower motor inoperative in all settings?
Yes
GO to S2.
No
Go To Pinpoint Test T. Pinpoint Test T: The Blower Motor Does Not Operate Correctly - DATC
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S2 CHECK THE BLOWER MOTOR SPEED TARGET POSITION (BLWR_T#) HVAC PID
- Enter the following diagnostic mode on the scan tool: BLWR_T# HVAC PID.
- Observe the BLWR_T# HVAC PID while increasing and decreasing the blower speed.
- Does the BLWR_T# HVAC PID reading change in all speeds between 0% and 100%?
Yes
GO to S3.
No
GO to S16.
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S3 CHECK FOR VOLTAGE TO THE BLOWER MOTOR
- Ignition OFF.
- Disconnect: Blower Motor C288.
- Ignition ON.
- Measure the voltage between ground and blower motor C288-2, circuit (BK), harness side.
- Is the voltage greater than 10 volts?
Yes
GO to S9.
No
CARRY OUT the blower motor relay component test.
If the relay tests OK, GO to S4.
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S4 CHECK THE RELAY SWITCH POWER CIRCUIT FOR AN OPEN
- Measure the voltage between ground and blower motor relay socket, circuit CH402 (YE/GN).
- Is the voltage greater than 10 volts?
Yes
GO to S5.
No
VERIFY Battery Junction Box (BJB) fuse 66 (40A) is OK. If OK, REPAIR circuit CH402 (YE/GN) for an open. TEST the system for normal operation.
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S5 CHECK THE RELAY COIL SUPPLY VOLTAGE
- Ignition OFF.
- Disconnect: Blower Motor Relay.
- Ignition ON.
- Measure the voltage between ground and blower motor relay socket, circuit CBP45 (YE).
- Is the voltage greater than 10 volts?
Yes
GO to S6.
No
VERIFY Smart Junction Box (SJB) fuse 45 (5A) is OK. If OK, REPAIR circuit CBP45 (YE) for an open. TEST the system for normal operation.
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S6 CHECK THE HVAC MODULE 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. 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.
- Connect a 12-volt test light between blower motor relay socket, circuit CBP45 (YE) and blower motor relay socket, circuit CH123 (VT/GN).
- Does the test light illuminate?
Yes
REPAIR circuit CH402 (YE/GN)/(BK) for an open. TEST the system for normal operation.
No
GO to S7.
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S7 CHECK CIRCUIT CH123 (VT/GN) FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: HVAC Module - DATC C228A.
- Ignition ON.
- Measure the voltage between ground and blower motor relay socket, circuit CH123 (VT/GN) and ground.
- Is any voltage present?
Yes
REPAIR circuit CH123 (VT/GN) for a short to voltage. TEST the system for normal operation.
No
GO to S8.
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S8 CHECK CIRCUIT CH123 (VT/GN) FOR AN OPEN
- Ignition OFF.
- Measure the resistance between and blower motor relay socket, circuit CH123 (VT/GN) HVAC module - DATC C228A-24, circuit CH123 (VT/GN), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to S16.
No
REPAIR circuit CH123 (VT/GN) for an open. TEST the system for normal operation.
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S9 CHECK FOR GROUND TO THE BLOWER MOTOR
- Ignition OFF.
- Disconnect: Blower Motor C288.
- Ignition ON.
- Select the highest blower speed setting.
- Measure the voltage between blower motor C288-2, circuit (BK), harness side and blower motor C288-1, circuit (BU), harness side.
- Is the voltage greater than 10 volts?
Yes
INSTALL a new blower motor. TEST the system for normal operation.
No
GO to S10.
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S10 CHECK CIRCUIT GD116 (BK/VT)/(BK/RD) FOR AN OPEN
- Ignition OFF.
- Disconnect: Blower Motor Speed Control C271.
- Measure the resistance between blower motor speed control C271-4, circuit (BK/RD), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
GO to S11.
No
REPAIR circuit GD116 (BK/VT)/(BK/RD) for an open. TEST the system for normal operation.
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S11 CHECK CIRCUITS VH101 (WH/VT)/(RD) AND CH102 (YE/BU)/(BN) FOR A SHORT TO GROUND
- Disconnect: HVAC Module - DATC C228B.
- Measure the resistance between ground and:
- blower motor speed control C271-1, circuit (RD), harness side.
- blower motor speed control C271-3, circuit (BN), harness side.
- Are the resistances greater than 10,000 ohms?
Yes
GO to S12.
No
REPAIR circuit VH101 (WH/VT)/(RD) or CH102 (YE/BU)/(BN) for a short to ground. TEST the system for normal operation.
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S12 CHECK CIRCUITS (BU), VH101 (WH/VT)/(RD) AND CH102 (YE/BU)/(BN) FOR A SHORT TO VOLTAGE
- Ignition ON.
- Measure the voltage between ground and:
- blower motor speed control C271-1, circuit (RD), harness side.
- blower motor speed control C271-3, circuit (BN), harness side.
- blower motor speed control C271-5, circuit (BU), harness side.
- Is any voltage present?
Yes
REPAIR circuit VH101 (WH/VT)/(RD), CH102 (YE/BU)/(BN) or (BU) for a short to voltage. TEST the system for normal operation.
No
GO to S13.
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S13 CHECK CIRCUITS VH101 (WH/VT)/(RD) AND CH102 (YE/BU)/(BN) FOR A SHORT TOGETHER
- Ignition OFF.
- Measure the resistance between blower motor speed control C271-1, circuit (RD), harness side and blower motor speed control module C271-3, circuit (BN), harness side.
- Is the resistance greater than 10,000 ohms?
Yes
GO to S14.
No
REPAIR circuit VH101 (WH/VT)/(RD) or CH102 (YE/BU)/(BN) for a short together. TEST the system for normal operation.
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S14 CHECK CIRCUIT (BU) FOR AN OPEN
- Measure the resistance between blower motor C288-1, circuit (BU), harness side and blower motor speed control C271-5, circuit (BU), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to S15.
No
REPAIR circuit (BU) for an open. TEST the system for normal operation.
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S15 CHECK CIRCUITS VH101 (WH/VT)/(RD) AND CH102 (YE/BU)/(BN) FOR AN OPEN
- Measure the resistance between blower motor speed control C271-1, circuit (RD), harness side and HVAC module - DATC C228B-16, circuit VH101 (WH/VT), harness side.
- Measure the resistance between blower motor speed control C271-3, circuit (BN), harness side and HVAC module - DATC C228B-15, circuit CH102 (YE/BU), harness side.
- Are the resistances less than 5 ohms?
Yes
INSTALL a new blower motor speed control. TEST the system for normal operation. If the condition returns, INSTALL a new HVAC module - DATC. TEST the system for normal operation.
No
REPAIR circuit VH101 (WH/VT)/(RD) or CH102 (YE/BU)/(BN) for an open. TEST the system for normal operation.
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S16 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.
- Operate the system and verify the concern is still present.
- Is the concern still present?
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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