Pinpoint Test R: The Blower Motor Is Inoperative - DATC System
Climate Control System
Pinpoint Tests
Pinpoint Test R: The Blower Motor is Inoperative - DATC System
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 through circuit GD120 (BK/GN). The coil receives voltage from the HVAC module - Dual Automatic Temperature Control (DATC) through circuit CH123 (VT/GN) when the HVAC module - DATC is ON. Voltage is supplied to the relay contacts from circuit SBB16 (VT/RD). When the relay coil is energized, voltage is delivered to the blower motor through circuit CH402 (YE/GN). Ground for the motor is provided through circuit VH301 (YE/BU) from the blower control module. Ground for the blower control module is provided by circuit GD140 (BK/GN).
This pinpoint test is intended to diagnose the following:
- Fuse(s)
- Wiring, terminals or connectors
- Blower motor control module
- HVAC module - DATC
- Blower motor relay
- Blower motor
PINPOINT TEST R: THE BLOWER MOTOR IS INOPERATIVE - DATC SYSTEM
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R1 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 R2.
No
Go To Pinpoint Test Q. Pinpoint Test Q: The Blower Motor Does Not Operate Correctly - Manual Climate Control
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R2 CHECK FOR VOLTAGE TO THE BLOWER MOTOR
- Ignition OFF.
- Disconnect: Blower Motor C2004.
- Ignition ON.
- Measure the voltage between ground and blower motor C2004-1, circuit CH402 (YE/GN), harness side.
- Is the voltage greater than 10 volts?
Yes
GO to R3.
No
GO to R8.
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R3 CHECK CIRCUIT GD140 (BK/GN) FOR AN OPEN
- Ignition OFF.
- Disconnect: Blower Motor Speed Control C271.
- Measure the resistance between ground and blower motor speed control C271-5, circuit GD140 (BK/GN), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to R4.
No
REPAIR circuit GD140 (BK/GN) for an open. TEST the system for normal operation.
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R4 CHECK CIRCUIT VH301 (YE/BU) FOR AN OPEN
- Measure the resistance between blower motor C2004-2, circuit VH301 (YE/BU), harness side and blower motor speed control C271-4, circuit VH301 (YE/BU), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to R5.
No
REPAIR circuit VH301 (YE/BU) for an open. TEST the system for normal operation.
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R5 CHECK THE BLOWER MOTOR
- Connect: Blower Motor C2004.
- Connect a fused jumper lead between blower motor speed control C271-4, circuit VH301 (YE/BU), harness side and C271-5, circuit GD140 (BK/GN), harness side.
- Ignition ON.
- Does the blower motor operate?
Yes
GO to R6.
No
INSTALL a new blower motor. TEST the system for normal operation.
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R6 CHECK CIRCUIT CH217 (BN) FOR AN OPEN OR SHORT TO GROUND
- Ignition OFF.
- Remove the fused jumper lead from blower motor speed control C271.
- Disconnect: HVAC Module - DATC C228b.
- Measure the resistance between:
- HVAC module - DATC C228b-4, circuit CH217 (BN), harness side and blower motor speed control C271-3, circuit CH217 (BN), harness side.
- ground and HVAC module - DATC C228b-4, circuit CH217 (BN), harness side.
- Is the resistance less than 5 ohms between the HVAC module - DATC and the blower motor speed control and greater than 10,000 ohms between the HVAC module - DATC and ground?
Yes
GO to R7.
No
REPAIR circuit CH217 (BN) for an open or a short to ground. TEST the system for normal operation.
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R7 CHECK THE HVAC MODULE OUTPUT
- Connect: HVAC Module - DATC C228b.
- Connect: Blower Motor Speed Control C271.
- Ignition ON.
- Adjust the blower motor speed to HI.
- Measure the voltage between ground and HVAC module - DATC C228b-4, circuit CH217 (BN), harness side by back-probing the HVAC module - DATC C228b.
- Is the voltage within 2 volts of battery voltage?
Yes
INSTALL a new blower motor speed control. TEST the system for normal operation.
No
GO to R14.
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R8 CHECK CIRCUIT CH402 (YE/GN) FOR AN OPEN
- Ignition OFF.
- Disconnect: Blower Motor Relay.
- Measure the resistance between blower motor relay socket pin 5, circuit CH402 (YE/GN) and blower motor C2004-1, circuit CH402 (YE/GN), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to R9.
No
REPAIR circuit CH402 (YE/GN) for an open. TEST the system for normal operation.
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R9 CHECK CIRCUIT GD120 (BK/GN) FOR AN OPEN
- Measure the resistance between ground and blower motor relay socket pin 1, circuit GD120 (BK/GN).
- Is the resistance less than 5 ohms?
Yes
GO to R10.
No
REPAIR circuit GD120 (BK/GN) for an open. TEST the system for normal operation.
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R10 CHECK CIRCUIT SBB16 (VT/RD) FOR VOLTAGE
- Measure the voltage between ground and blower motor relay socket pin 3, circuit SBB16 (VT/RD).
- Is the voltage greater than 10 volts?
Yes
GO to R11.
No
VERIFY Battery Junction Box (BJB) fuse 16 (40A) is OK. If OK, REPAIR circuit SBB16 (VT/RD) for an open. TEST the system for normal operation.
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R11 CHECK THE HVAC MODULE OUTPUT
- Ignition ON.
- Measure the voltage between blower motor relay socket pin 1, circuit GD120 (BK/GN) and socket pin 2, circuit CH123 (VT/GN).
- Is the voltage greater than 10 volts?
Yes
INSTALL a new blower motor relay. TEST the system for normal operation.
No
GO to R12.
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R12 CHECK CIRCUIT CH123 (VT/GN) FOR SHORT TO GROUND
- Ignition OFF.
- Disconnect: HVAC Module - DATC C228b.
- Measure the resistance between ground and blower motor relay socket pin 2, circuit CH123 (VT/GN).
- Is the resistance greater than 10,000 ohms?
Yes
GO to R13.
No
REPAIR circuit CH123 (VT/GN) for a short to ground. TEST the system for normal operation.
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R13 CHECK CIRCUIT CH123 (VT/GN) FOR AN OPEN
- Measure the resistance between HVAC module - DATC C228b-13, circuit CH123 (VT/GN), harness side and blower motor relay socket pin 2, circuit CH123 (VT/GN).
- Is the resistance less than 5 ohms?
Yes
GO to R14.
No
REPAIR circuit CH123 (VT/GN) for an open. TEST the system for normal operation.
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R14 CHECK MODULE CONNECTION
- Carry out the HVAC Module - Dual Automatic Temperature Control (DATC) Cold Boot Process. Alternate Diagnostic Methods - HVAC Module - Dual Automatic Temperature Control
- Carry out the HVAC Module - Dual Automatic Temperature Control (DATC) On-Demand Self-Test. Alternate Diagnostic Methods - HVAC Module - Dual Automatic Temperature Control
- Operate the system.
- Does the concern return?
Yes
INSTALL a new HVAC module - DATC. 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.
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