Pinpoint Test R: The Blower Motor Is Inoperative - DATC
Climate Control System
Pinpoint Tests
Pinpoint Test R: 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 relay coil and switch is supplied voltage. 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 control module 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.
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
- Battery Junction Box (BJB)
PINPOINT TEST R: THE BLOWER MOTOR IS INOPERATIVE - DATC
-------------------------------------------------
R1 VERIFY THE BLOWER MOTOR OPERATION
- Ignition ON.
- Press the PANEL button on the HVAC module. 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 S. Pinpoint Test S: The Blower Motor Does Not Operate Correctly - DATC
-------------------------------------------------
R2 CHECK FOR VOLTAGE TO THE BLOWER MOTOR
- Ignition OFF.
- Disconnect: Blower Motor C288 .
- Ignition ON.
- Measure the voltage between blower motor C288-1, circuit CH402 (YE/GN), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to R3.
No
GO to R9.
-------------------------------------------------
R3 CHECK FOR VOLTAGE TO THE BLOWER MOTOR CONTROLLER
- Ignition OFF.
- Disconnect: Blower Motor Speed Control C297 .
- Ignition ON.
- Measure the voltage between blower motor speed control C297-4, circuit CH402 (YE/GN), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to R4.
No
REPAIR circuit CH402 (YE/GN) for an open. TEST the system for normal operation.
-------------------------------------------------
R4 CHECK CIRCUIT GD138 (BK/WH) FOR AN OPEN
- Ignition OFF.
- Measure the resistance between blower motor speed control C297-1, circuit GD138 (BK/WH), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
GO to R5.
No
REPAIR circuit GD138 (BK/WH) for an open. TEST the system for normal operation.
-------------------------------------------------
R5 CHECK CIRCUIT VH301 (YE/BU) FOR AN OPEN
- Measure the resistance between blower motor C288-2, circuit VH301 (YE/BU), harness side and blower motor speed control C297-2, circuit VH301 (YE/BU), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to R6.
No
REPAIR circuit VH301 (YE/BU) for an open. TEST the system for normal operation.
-------------------------------------------------
R6 CHECK THE BLOWER MOTOR
- Connect: Blower Motor C288 .
- Connect a fused jumper lead between blower motor speed control C297-2, circuit VH301 (YE/BU), harness side and C297-1, circuit GD138 (BK/WH), harness side.
- Ignition ON.
- Does the blower motor operate?
Yes
GO to R7.
No
INSTALL a new blower motor. REFER to Climate Control Service and Repair. TEST the system for normal operation.
-------------------------------------------------
R7 CHECK CIRCUIT VH101 (WH/VT) FOR A SHORT TO GROUND
- Ignition OFF.
- Remove the fused jumper lead from blower motor speed control C297.
- Disconnect: HVAC Module - Dual Automatic Temperature Control (DATC) C228B .
- Measure the resistance between blower motor speed control C297-3, circuit VH101 (WH/VT), harness side and ground.
- Is the resistance greater than 10,000 ohms?
Yes
GO to R8.
No
REPAIR circuit VH101 (WH/VT) for a short to ground. TEST the system for normal operation.
-------------------------------------------------
R8 CHECK CIRCUIT VH101 (WH/VT) FOR AN OPEN
- Ignition OFF.
- Measure the resistance between blower motor speed control C297-3, circuit VH101 (WH/VT), harness side and HVAC module - DATC C228B-16, circuit VH101 (WH/VT), harness side.
- Is the resistance less than 5 ohms?
Yes
INSTALL a new blower motor speed control. REFER to Climate Control Blower Motor Speed Control. TEST the system for normal operation. If the blower motor is still inoperative, GO to R15.
No
REPAIR circuit VH101 (WH/VT) for an open. TEST the system for normal operation.
-------------------------------------------------
R9 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 C288-1, circuit CH402 (YE/GN), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to R10.
No
REPAIR circuit CH402 (YE/GN) for an open. TEST the system for normal operation.
-------------------------------------------------
R10 CHECK THE RELAY COIL SUPPLY VOLTAGE
- Measure the voltage between blower motor relay socket pin 1, circuit CBB57 (BN/GN) and ground.
- Is the voltage greater than 10 volts?
Yes
GO to R11.
No
VERIFY Smart Junction Box (SJB) fuse 57 (10A) is OK. If OK, REPAIR circuit CBB57 (BN/GN) for an open. TEST the system for normal operation.
-------------------------------------------------
R11 CHECK THE RELAY SWITCH POWER CIRCUIT FOR AN OPEN
- Measure the voltage between blower motor relay socket pin 3, circuit CBB32 (VT/RD) and ground.
- Is the voltage greater than 10 volts?
Yes
GO to R12.
No
VERIFY BJB fuse 32 (40A) is OK. If OK, REPAIR circuit CBB32 (VT/RD) for an open. TEST the system for normal operation.
-------------------------------------------------
R12 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. 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 ON.
- Connect a 12-volt test light between blower motor relay socket pin 1, circuit CBB57 (BN/GN) and socket pin 2, circuit CH123 (VT/GN).
- Does the test light illuminate?
Yes
INSTALL a new blower motor relay. TEST the system for normal operation.
No
GO to R13.
-------------------------------------------------
R13 CHECK CIRCUIT CH123 (VT/GN) FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: HVAC Module - DATC C228A .
- 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. TEST the system for normal operation.
No
GO to R14.
-------------------------------------------------
R14 CHECK CIRCUIT CH123 (VT/GN) FOR AN OPEN
- Measure the resistance between HVAC module - DATC C228A-24, 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 R6.
No
REPAIR circuit CH123 (VT/GN) for an open. TEST the system for normal operation.
-------------------------------------------------
R15 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. REFER to Climate Control Heating Ventilation Air Conditioning (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.
-------------------------------------------------